Whether you’re a DIYer, automotive technician, or marine electrician, you may have come across heat shrink solder connectors (also called solder seal connectors, solder sleeves, or self-soldering wire connectors). These connectors allow you to join wires with a soldered connection and seal it in one simple step – no crimping tool or soldering iron required. They consist of a transparent dual-wall heat shrink tube with a low-melt solder ring in the middle and adhesive lining at the ends. When heated, the solder ring melts to solder the wires together, while the tubing shrinks and the inner adhesive melts to seal the connection. The result is a soldered connector that is electrically solid and waterproof, combining the conductivity of solder with the strain relief of a glued heat shrink sleeve.
One key spec you’ll notice when shopping for these connectors is the shrink ratio – typically listed as 2:1 or 3:1. For example, Haisstronica’s popular 180pcs Heat Shrink Solder Seal Wire Connectors Kit (AWG 26–10) uses high-quality adhesive-lined tubing with a specified shrink ratio. But what exactly does 2:1 vs 3:1 mean for your wire connections? And how do you ensure you’re picking the right size connector for your wire gauge and insulation thickness? In this buying guide, we’ll dive deep into what “shrink ratio” really means, how to size solder connectors by AWG vs insulation OD, and answer FAQs to help you choose the right solder & seal solution for your needs.
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What “Shrink Ratio” Really Means for Solder Connectors
Before we compare 2:1 vs 3:1, let’s clarify the concept of heat shrink ratio. Shrink ratio is expressed as a number like 2:1 or 3:1, representing the tubing’s original diameter to its shrunken diameter. For instance, a 2:1 shrink ratio means the tubing will shrink to half its original diameter when heated, whereas 3:1 means it will shrink to one-third of its original diameter. In other words, a higher ratio indicates the tubing can shrink more aggressively.
Why does this matter for solder seal connectors? The shrink ratio determines how tightly the connector’s tubing can ultimately wrap around your wires after heating. A higher ratio 3:1 heat shrink solder connector starts out with a larger expanded diameter and then shrinks down much more, allowing it to accommodate a wider range of wire sizes and then still get tight enough to seal. By contrast, a 2:1 connector will only shrink to half its starting size, which is fine if your wire’s insulation diameter is already close to the tubing’s original size, but it offers less range to handle variability.
To put it simply, 2:1 vs 3:1 is about how much the tubing can contract:
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2:1 Shrink Ratio: Shrinks to 50% of its supplied diameter. Common in many standard or budget solder sleeve connectors. Good for situations where the wire/jacket size closely matches the connector’s pre-shrink size. It tends to be a bit more compact and is usually cost-effective. However, with only a 2x shrink capability, it has less flexibility if there’s a big size difference along the splice – it might not fully tighten on very thin sections, and it can’t accommodate as wide a range of cable sizes in one connector.
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3:1 Shrink Ratio: Shrinks to ~33% (one-third) of its original diameter. This higher ratio gives much more contraction. A 3:1 connector can start larger (to fit over bulky connectors or thicker insulation) and then shrink down much smaller, biting down around the wires and insulation to eliminate voids. This is ideal for irregular shapes or varying diameters – for example, if you’re splicing a thick-jacket wire to a thinner one, a 3:1 can still snug both sides. 3:1 solder seal connectors are considered the “sweet spot” for versatility: they provide a tight, secure fit and superior sealing, and are widely used in automotive, marine, and industrial applications where extra shrink performance ensures a weatherproof seal. The trade-off is slightly thicker tubing walls once shrunk (since it shrinks more, the wall concentrates and can become a bit stiffer).
Why choose one over the other? A lot comes down to the application’s demands:
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Sealing and Protection: A higher shrink ratio often means a more complete wrap and thus better environmental seal. In fact, a 3:1 or higher can provide more complete coverage of the conductor and adhesive, reducing risk of moisture ingress. If you need a truly waterproof solder connection, a 3:1 connector is more likely to achieve a tight seal on varying wire sizes. 2:1 solder connectors still insulate, but they leave less margin for error in achieving a perfect seal if the wire doesn’t fill most of the tube.
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Range of Wire Sizes: With 2:1, each connector size covers a narrower wire gauge range. A 3:1 connector can cover a wider range of diameters because it starts bigger and shrinks more. For example, suppose you have a connector that is 6mm inner diameter initially: a 2:1 version can shrink down to ~3mm, whereas a 3:1 version can shrink to ~2mm. That difference could mean sealing a 16 AWG wire vs being able to go down to 20 AWG in the same size connector. Higher shrink ratio = more flexibility to use one connector size for multiple wire sizes.
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Tightness of Fit: In cases where your wire’s insulation is much smaller than the connector’s expanded diameter, a 2:1 may not shrink enough to grip it tightly, leaving a loose fit or air gaps. A 3:1 will shrink more and clamp down tighter, which is especially important for the adhesive lining to do its job (it needs to compress and ooze slightly to fill gaps). As a practical rule, if your measured wire jacket OD is near the minimum shrinkable diameter of a sleeve, opting for a 3:1 heat shrink solder sleeve ensures the adhesive can really compress and seal out air.
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Cost and Material: Generally, 2:1 tubing is very common and often a bit cheaper, whereas 3:1 may use more material or special formulations (often 3:1 are dual-wall with adhesive by default). That said, the cost difference in small connectors is usually minor, and the performance benefit of 3:1 in critical splices (especially for automotive/marine) often outweighs a few pennies saved per connector.
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It’s worth noting that even higher ratios like 4:1 exist (and Haisstronica offers some 4:1 solder connectors in specialized kits). A 4:1 ratio can shrink to 25% of original – these are great “problem solvers” for extreme size differences or odd situations (like one side of a splice has a thick silicone jacket or multiple conductors). They give you the most shrink range and forgiveness if you picked a connector slightly too large, but 4:1 connectors are less common and typically a bit more expensive. For most users, 3:1 strikes the best balance between versatility and performance, while 2:1 works for standard use when wire sizes are consistent.
Are there any downsides to 3:1? Not many, but a couple of minor points to mention: When fully shrunk, a higher ratio tubing will have thicker walls (since all that extra material has to go somewhere). This can make the finished splice a little more rigid or stiff compared to a 2:1 sleeve. In most cases, the added stiffness is actually helpful for strain relief, but if maximum flexibility is needed in a tight spot, a 2:1 might be slightly more pliable. Also, higher ratio tubes may require a bit more care in heating evenly – because they shrink more, uneven heating could cause one side to start shrinking and potentially pull or deform before the other side (an asymmetrical shrink), though this is rarely an issue if you rotate the splice while heating. Overall, these are small considerations; both 2:1 and 3:1 solder & heat shrink connectors are designed to be heated gradually and evenly for best results.
Key takeaway: A 3:1 solder connector gives you a tighter seal and more wiggle room in sizing, which is why it’s often preferred for critical or outdoor connections. A 2:1 connector is perfectly adequate for many jobs, especially if you match the exact sizes well and need a compact, economical solution. If unsure, err on the side of a higher shrink ratio to ensure a snug, sealed result – as one engineering guide puts it, a higher shrink ratio covers a wider range of diameters and provides more complete moisture protection. In short, 2:1 vs 3:1 is not about one being “good vs bad,” but about choosing the right tool for the job.
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Sizing: AWG vs Insulation OD for Solder & Seal Connectors
Choosing the correct size solder seal connector for your wires is crucial. These connectors are typically sold in standard sizes/color codes corresponding to wire gauge ranges (AWG). For example, common color codes are: White (26–24 AWG), Red (22–18 AWG), Blue (16–14 AWG), Yellow (12–10 AWG). The solder ring inside and the length of the connector are engineered for that range of copper conductor sizes. However, AWG alone isn’t the whole story.
To ensure a reliable, sealed splice, you must consider both the conductor gauge AND the insulation outer diameter (OD) of your wires:
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Start with AWG (and color code): The wire’s gauge tells you the size of the copper conductor. Always choose a connector that covers your wire’s AWG. If you use too small a connector on a thicker wire, the wire won’t even fit in or the solder volume will be insufficient to bond it. Conversely, using a connector meant for a much larger gauge on a thin wire means the solder ring may not adequately melt into the tiny strands, and the tubing may not shrink tight enough. For instance, if you try to put an AWG 12 wire into a Blue (16–14 AWG) solder sleeve, there won’t be enough solder to fully envelop the larger strands (resulting in a weak joint). If you put an AWG 20 wire into that same Blue connector, the wire is so thin that you’ll likely never get the heat shrink to shrink tightly enough to seal – you’d end up with a loose tube around the insulation. So, first and foremost, use the correct color/AWG range as specified by the connector kit.
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Check the Insulation OD: Here’s where many people, especially beginners, might get tripped up. Two wires of the same gauge can have very different insulation thickness depending on the wire type and application. For example, a 16 AWG wire with thin PVC insulation might be only ~2.5 mm in outer diameter, while a 16 AWG high-temperature silicone wire could be 3.5–4 mm OD due to the thicker, more flexible silicone jacket. Marine-grade wires, often being fine-stranded and heavily insulated, can be significantly thicker overall than a typical PVC automotive wire of the same AWG. According to a Panduit wire selection guide, a 24 AWG insulated wire might have an outside diameter anywhere from about 0.059 inches up to 0.088 inches, depending on the insulation type – that’s nearly a 50% difference! In practical terms, this means an 18–22 AWG solder connector that fits one 20 AWG wire snugly might be too tight or too loose on another 20 AWG wire if the insulation differs.
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How to size by OD: Quality connector manufacturers (Haisstronica included) will usually publish the dimensions of their solder sleeves – notably the inner diameter (ID) of the tubing before shrinking and the minimum ID after full shrink. When in doubt, measure your wire’s insulation diameter (use calipers for accuracy) and check that against the connector’s specs. You want the unshrunk ID to be just large enough to slip over the wire insulation easily, and the fully shrunk ID to be small enough to grip the insulation tightly. The adhesive rings inside the connector should end up compressing onto the wire jacket.
If you can’t find exact specs, a good rule of thumb is that after shrinking, the tubing should be uniformly compressed onto the wire jacket, with no large gaps or loose spots near the adhesive. The adhesive should visibly wet the jacket. If you see gaps or the tubing isn’t gripping the insulation, the connector is likely too large for that wire (or wasn’t heated enough). Using a higher shrink ratio connector (like 3:1) can help in these borderline cases, because it shrinks more and can take up the slack.
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Thick vs Thin Insulation Scenarios: If you’re working with fine-stranded silicone wire with a thick rubbery jacket, or something like double-insulated marine cable, lean towards connectors with a 3:1 (or even 4:1) shrink ratio. These will better accommodate the thicker OD and still seal down. For example, splicing two silicone-insulated wires, a 3:1 connector ensures the tubing can really hug that soft, thick jacket. On the other hand, if you have a wire with an exceptionally thin insulation (like some PTFE Teflon wires or enamel-coated magnet wire), a 2:1 might suffice since there’s not much jacket to shrink onto – but be very precise with heating to ensure even shrink and no “cold” spots. (In fact, such thin PTFE wires are often in delicate electronics where you might use a different connector type entirely.)
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Don’t purely trust color if mixing brands: While most brands follow the standard color-to-AWG mapping, there can be slight differences in the tubing size or solder ring amount. Always double-check the package or spec sheet. For instance, Haisstronica’s Red connectors cover 22–18 AWG, but a off-brand red connector might claim 20–16 AWG – the overlap is similar but not identical. If possible, use the chart provided with the connectors (better kits have the AWG ranges clearly labeled on the case for each color).
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The strip length and overlap matter too: This isn’t exactly about connector sizing, but it’s related to getting a good solder joint. Make sure you strip enough insulation so that the exposed wire from each side, when inserted, overlaps under the solder ring. Typically about 6–7 mm (1/4 inch) strip on each side for small reds/blues, and ~8–10 mm for larger yellows, so that you have ~3–5 mm of bare wire overlapping under the solder in the middle. If you don’t strip enough, the solder might only bond on one side. If you strip way too much, you might have exposed copper beyond the tubing after shrinking. Most kits will guide you on strip length. Having the right amount ensures the soldered wire connectors bond properly internally.
In summary, size your solder connectors by AWG and by wire OD. AWG ensures the solder volume is appropriate; OD ensures the heat shrink can do its job sealing. If your wire’s insulation is especially thick for its gauge, choose a connector on the larger end of the gauge range or one with a higher shrink ratio. If the insulation is thin, you can use the smaller end of the connector range, but heat carefully. It may also be wise to test-fit one connector on your wire before doing a critical job – slide the unshrunk connector over the stripped wire end to see that it covers the insulation, and after heating, inspect that the adhesive has melted out and no gaps remain.
Pro Tip: Haisstronica’s connector kits make this easy by providing all common sizes and listing the AWG ranges on the box. For example, the 180pcs or 340pcs automotive wire connectors kit from Haisstronica clearly labels which color corresponds to which AWG, covering 26–10 AWG in a tidy assortment. This takes the guesswork out of picking the right wire connector with solder – you can simply match the color to your wire gauge, then double-check fit if your insulation is unusual. Having an organized kit on hand means you’ll always have the right size solder splice connector when you need it.
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FAQs on Solder Seal Connectors
Finally, let’s address some common questions and concerns about using these solder seal heat shrink connectors.
Q: Are solder seal connectors really waterproof and reliable for critical use?
A: When properly installed, quality solder & seal connectors create a water-resistant, sealed splice that is very secure. The dual-wall tubing with adhesive forms a tight bond to the wire insulation, and the soldered joint is encapsulated inside. This effectively blocks out moisture and provides strain relief. In fact, these are often marketed as “marine grade” connectors for use in boats, automotive, and outdoor wiring, and they can achieve waterproof ratings near IP67 when done correctly. Independent guides note that dual-wall heat shrink with adhesive is key to a watertight seal. As for electrical/mechanical reliability: for most DIY, automotive, and marine applications, a well-made soldered wire splice is strong both electrically and physically. The tensile strength of a good solder joint in these connectors is usually similar to a crimp. That said, no connector is foolproof – if overheated (charring the tubing) or underheated (solder not fully melted), failures can occur.
In high-vibration or critical safety environments (e.g. aerospace, race cars, or industrial machinery subject to constant motion), some experts and standards prefer crimped connections over solder. This is because a soldered joint can act as a stress riser if the wire is flexing a lot, potentially leading to fatigue breakage if not strain-relieved. However, the beauty of solder seal connectors is that the heat shrink does provide strain relief. As Haltech (a performance automotive company) points out, the risk of vibration-induced cracking in solder joints is generally preventable with proper strain relief – specifically by using adhesive-lined heat shrink to support the wire and joint. That’s exactly what these connectors do by design. Furthermore, one industry blog notes that when done properly, a soldered connection will withstand vibration and shock just as well as a crimp connection. In short, for automotive and marine use, solder seal connectors are very reliable. Just be sure to execute them correctly: use the right size connector, fully melt the solder and adhesive (you should see a fillet of shiny solder and adhesive ooze at the ends), and let it cool undisturbed so the joint solidifies. For critical circuits (airbag sensors, etc.) or compliance with specific regulations, always follow the manufacturer or industry guidelines – in some cases a crimp or other connector might be mandated. But for the vast majority of wiring fixes or projects, these sealed solder connectors are more than up to the task and indeed combine the best of soldering and crimping (a solid bond plus a sealed jacket).
Q: 2:1 vs 3:1 – which shrink ratio should I choose for my application?
A: It depends on your priorities. Use 3:1 heat shrink solder connectors for maximum versatility and sealing. For example, if you’re working on a marine or outdoor wiring repair, or dealing with wires that have thicker insulation (like premium silicone automotive wire or multiple wires together), the 3:1 will ensure a tight seal against water and give you room to fit over any components and then shrink fully. A 3:1 also helps if you’re not 100% sure about the wire diameter – it’s more forgiving and will shrink down snug even if you over-estimated the size. Use 2:1 connectors for more standard jobs where wire sizes are very consistent and you want a slightly smaller final profile. They work well for electronics projects, indoor use, or when replacing connectors on a known harness where the wire spec is standard (e.g., typical PVC insulated wires where the connector’s range is a perfect match). In practice, many automotive connector kits now favor 3:1 ratios because vehicles often have varying insulation thicknesses and exposure to the elements, so the extra sealing capability is worth it. If you already have a kit of 2:1 connectors, don’t worry – just be sure to choose the correct size for each wire (and consider adding some extra adhesive-lined heat shrink over the joint if you want to beef up the waterproofing). But if buying new, we recommend going with shrink sleeves that are 3:1 in most cases, as they give the best of both worlds.
Q: Do I need a special tool to heat these solder connectors, or will a lighter work?
A: The ideal tool is a heat gun – preferably with a concentrator nozzle – so you can apply controlled, even heat around the connector. A heat gun at around 300°C (572°F) can melt the solder ring typically in ~10-20 seconds, depending on the connector size. Start by focusing heat at the solder ring in the middle until you see it liquify, then sweep to the ends to fully shrink the tubing and melt the adhesive. You’ll know it’s done when the solder visibly flows into the wire strands and you see adhesive bubbling out at the edges of the tubing. Using a proper heat gun ensures you don’t burn the tubing. Can you use a lighter or torch? In a pinch, yes – many people do successfully use a small butane torch or even the flame of a lighter. But be very careful! An open flame has a higher risk of charring the heat shrink or not heating evenly. If you go this route, keep the flame moving and not too close. There are also purpose-made mini heat torches that run on butane that can work well. Never use an open flame near flammable vapors (gasoline, etc.) and avoid it in confined spaces. For consistent results, an electric heat gun is best; even a basic one is fairly inexpensive. The good news is that you do not need a soldering iron at all – the solder is built-in, so you’re essentially just using heat to activate the solder and shrink the tube. This makes these connectors solderless connectors from the user’s perspective (no manual soldering), even though the joint itself is a true solder bond. So, invest in a decent heat gun if you plan to use solder seal connectors regularly – it will pay off in ease and reliability.
Q: How do solder seal connectors compare to crimp connectors? (Solder vs Crimp)
A: This is a classic debate in wiring! In general, both methods can produce reliable connections if done correctly, but they each have pros and cons:
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A crimp connector (especially an insulated crimp butt splice with heat shrink) relies on mechanically deforming a metal ferrule around the wires. A good crimp, done with the right tool, creates a solid gas-tight joint and is very fast – no heat needed. Crimping is often favored in mass production and by some industries because it’s consistent and doesn’t heat the wire (no risk of overheating components). Crimp connectors are truly solderless wire connectors – you only need a crimp tool. However, crimping does require the correct size connector for the wire and a quality ratcheting crimper to achieve the proper compression. A bad crimp (using pliers or the wrong die) can result in a weak connection that pulls out or corrodes.
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Soldering a connection (the traditional way with solder wire and iron) gives an excellent electrical bond and is very compact, but it’s more skill-intensive and time-consuming for multiple joints. The solder can wick into the wire and if not supported, the junction of soldered and unsoldered wire can be a break point under flex (hence the need for strain relief). Solder seal connectors attempt to combine the best of both: the low-resistance solder bond and the encapsulation and strain relief of a shrink tube. They eliminate the need for a crimping tool, making them very user-friendly for hobbyists and techs in the field.
In terms of performance, for most wiring tasks you’ll find solder seal (heat shrink) connectors to be more convenient than crimp-and-shrink connectors. They’re especially great for repairs in tight spots or when you don’t have access to a full toolbox – you literally just need the connectors and a heat source. Many automotive and marine enthusiasts find them superior for aftermarket work because they ensure a sealed connection without the bulk of a crimp terminal. On the flip side, professional installers might still prefer crimps for critical harnesses because of long-term track records and standards compliance. The “solder vs crimp” question ultimately comes down to environment and execution: a badly made solder joint is worse than a proper crimp, and vice versa. But with solder seal connectors, if you follow the instructions, it’s actually very easy to get a near-perfect solder joint every time (the solder ring has just the right amount and the clear sleeve lets you inspect the result).
One consideration: codes/standards. In marine and automotive, these solder connectors are generally accepted for repairs and new installations (they’re widely sold as automotive waterproof connectors kits). For aviation or mission-critical systems, regulations might require crimped or screwed terminals instead of solder splices. Always check if there are specific rules for your project (for instance, some marine certification might call for crimped terminals on battery cables, etc., but for general wiring these solder sleeves are fine).
In summary, crimp vs solder doesn’t have to be an either/or – each has its place. Solder seal connectors effectively give you a soldered, sealed joint that in many scenarios meets or exceeds the performance of a crimped joint. They are especially handy for one-off fixes and DIY builds. If you have a quality crimp tool and connectors, crimping is also great. If you don’t, or you want the extra sealing, these shrink solder connectors are the way to go. Think of them as another tool in your toolbox. (Fun fact: some installers even double up – they’ll crimp a connection and then slide a solder seal connector over it without using the solder ring, just to use the heat shrink and adhesive for sealing. This isn’t necessary, but it shows how valued the sealing feature is.)
Q: Any tips for getting the best results with these connectors?
A: Here are a few quick tips:
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Prep the wire properly: Strip the correct length as mentioned earlier, and don’t tin the wires (do not pre-solder) – insert them clean and dry. Twisting stranded wire lightly can help it feed into the sleeve without fraying, but don’t over-twist into a point. The solder in the connector has flux, so you typically don’t need additional flux. Just ensure the wires overlap under the solder ring.
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Position carefully: Center the solder ring over the bare copper overlap, and make sure the colored adhesive bands are positioned over the insulation on each side (not over the bare copper). This way, when heated, the adhesive will bond to the intact insulation on each wire, sealing the ends of the connector.
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Use the right heat technique: As mentioned, a heat gun is best. Begin heating in the middle at the solder ring until you see the solder fully melt and flow. You might see it suddenly turn shiny and get sucked into the wire strands – that’s good. Then immediately move the heat to the ends to shrink the tubing and melt the adhesive. You want to see a bit of adhesive ooze out at each end of the connector – that’s confirmation of a good seal. Continue to sweep back and forth a bit to ensure the entire tube is shrunk evenly. Don’t overdo it – once the solder has melted and the tubing has fully shrunk and you see adhesive, stop heating. Overheating can scorch the tube or boil the adhesive.
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Let it cool: This is important – once you remove heat, let the splice cool for at least 10-15 seconds before disturbing it. The solder needs to solidify. If you tug the wires while it’s still hot, you could pull the joint apart or create a “cold” solder spot. After it cools, do a gentle pull test on the wires – a correctly made solder butt splice will be very strong; the wire should break before the joint does in most cases.
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Keep it dry until sealed: If you’re working in a damp environment, try to keep moisture out of the splice while you’re heating. It’s rare, but if water is present inside the tube while you heat, it could create steam and pressure. Best to make connections in a dry condition and then once sealed, they can encounter water.
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Practice on a spare: If you’re new to these, use an extra connector on some scrap wire to get a feel for the heating time and signs. It’s straightforward, but a quick practice never hurts.
Following these tips will ensure your heat shrink solder connectors perform as advertised – giving you a neat, durable, sealed connection with minimal fuss.
Our Top User-friendly Picks
Haisstronica’s hot-melt formula pairs solder and heat shrink to lock out moisture while boosting conductivity. Our heat shrink solder connectors flow evenly around strands, then cool to a rigid seal. Clean, repeatable soldering connections mean fewer callbacks and long-term reliability in marine, auto, and outdoor installs.
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Conclusion: Choosing the Right Soldered Connector
Both 2:1 and 3:1 solder seal connectors are game-changers for making quick, solid wire splices. To wrap up, remember the core points:
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Shrink ratio matters – a 3:1 connector shrinks more and generally gives a tighter, more waterproof seal than a 2:1. If you’re often dealing with varying wire sizes or want the best protection, go with 3:1 connectors. Use 2:1 when the fit is already close and you value a smaller profile or lower cost for routine jobs.
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Size by AWG and OD – Always verify that the connector size (color) matches your wire gauge, and consider the insulation thickness. When in doubt, measure the wire’s OD and ensure the connector’s shrink range covers it. This guarantees the adhesive can properly bond and you get a void-free seal.
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Quality connectors count – Not all solder connectors are equal. Stick with reputable brands (like Haisstronica) that use good solder alloy, plenty of adhesive, and clear tubing. They’ll have transparent tubing so you can inspect the joint and printed or color-coded size indicators for ease. A cheap solder stick connector might skimp on solder or adhesive, leading to a weaker connection.
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Follow best practices – Use the right heat tool, take your time to heat evenly, and ensure the solder melts fully. A well-made solder seal connection will be shiny, with solder flowed into the wires, and adhesive visibly sealing the ends. That connector will be strong, electrically low-resistance, and weather-tight.
By understanding what shrink ratio really means and how to choose the correct connector for your wire, you’ll make professional-grade splices that you can trust. Many DIYers and pros alike have found that these solder seal heat shrink connectors simplify wiring projects – from car stereo installs and trailer hookups to boat wiring and home DIY electronics. With this guide (and the right kit on hand), you can confidently fix or create wiring harnesses that are both electrically sound and protected from the elements. Happy wiring!
Sources:
RS Components
Zippertubing
HeatShrinkTubing.com
Haltech – Crimping vs Soldering
