Kuject Heat Shrink Solder Seal Wire Connectors Kit 120PCS, Waterproof Butt Connector Heat Shrink Electrical Terminals, Insulated Solderless Wiring Splice Connectors for Marine Automotive Boat Truck

I picked up the Kuject Solder Seal Heat Shrink Butt Connectors for some wiring projects, and honestly, they’ve made my life way easier. If you’ve ever struggled with messy connections or worrying about durability, these will be your new best friend.The best part? The solder ring inside melts perfectly when heated, creating a strong, clean connection without needing extra tools or messy soldering. Plus, the heat shrink sleeve seals everything tight and waterproof, which gives me confidence that my connections won’t fail even in tough conditions.I tested these on my car’s wiring and some home electronics, and every joint has held up great — no corrosion, no loosening, just solid connections. They’re also super easy to use, even if you’re not a pro.With 200 pieces, I have plenty to keep me stocked for future projects. Overall, I’m really happy with the quality and performance of these connectors — they definitely take the headache out of wiring jobs.

Solder wires together in seconds better and faster than using an iron and heat shrink. The only downsides are I wish they had a greater range of smaller sizes and some with shorter lengths

A little background: I've been doing electrical and electronics for over 40 years and was an aviation electronics tech in the US Navy so I've worked on everything from simple car/truck/trailer wiring, residential/commercial electrical, and electrical/electronics on military aircraft so I've dealt with wires as small as 24awg all the way up to 500 MCM (wires about 1" across) which means I've done a fair bit of splicing in my life. Now with that said nothing will replace a straight un-spliced wire but that's in a perfect world. Your sooner or later going to have to repair a wire or connect prewired devices to existing wiring. A solder joint is one of the best ways to do this and adding heat shrink to protect and insulate the splice has been the best method and next being a mechanical splice which is the next best thing. I found out about these via a YouTube video and of course looked on Amazon for them, I found so many different sellers and the reviews ranged from 1 Star to 5 Stars so I thought I would order some and give them a try. Glad I did because they work great and plan to buy more. From what I can see after using them and seeing the complaint reviews is a couple of things.#1 DO NOT USE A LIGHTER OR TORCH! Use a heat gun if you can. Remember these are basically made of plastic with some low temp solder inside. If you use a lighter or torch then you have to be very careful about how close to the splice you are and how long you concentrate that heat in one spot. I understand not everyone has a heat gun and if fixing wiring in a place you don't have an electrical outlet to plug one in will happen.#2 Make sure you have clean wire! By this I mean when you strip out the end of the wire it should be nice shiny copper, not corroded (copper turns green when corroded and in worse case black) and the reason is that the solder band inside the heat shrink does have some flux content to it but not enough to etch away that corrosion to allow a good flow of wire between the stands on the two wires your splicing.Tips: Make sure you strip out the end of the wire long enough for them to overlap one another and stay in the area of the solder sleeve. Make sure the copper is nice and clean (shiny). Applying heat to one end first to help hold one of the wires in place while you hold the other end in place with your hand. Keep your heat source (heat gun preferred) a good distance away from the splice, if it's not shrinking then move it a little closer until it starts to shrink or melt the solder band, if you see the heat shrink sleeve start to darken or burn your too close! Make sure your rotating the splice as your shrinking and soldering it, a common mistake when using this product or just heat shrink alone is that the person just holds it in once place and holds the heat source in one spot expecting it to heat the entire thing and shrink. If you see the insulation on the wire start to melt or bubble again you have the heat source too close to the wire or your concentrating that heat in one spot too long. In the picture I attach you can see the smallest splice that they have used to splice two wires (18-20 awg copper stranded, I don't remember) and the splice is still translucent and the solder flowed great (note the right side wire, the insulation is a little bubbled and thats my fault with the heat in one spot too long and also with that small of a gauge of wire it can heat up really quick).Over all being a little skeptical of the product based on the reviews I got it anyways and I'm glad I did! I planed on only using these on splices where they needed to be water proof but after using them and seeing how well they work I will use them for every splice from now on. Hope this helps others in making their decision on weather or not to buy and try these splices.

I use all the time and the joints keep strong

This is my third package

Excellent quality It really works and comes in different sizes

Who every came up with these should be given a medal. These take out the need for a soldering gun I used them to replace my fuel injector lines and they now have a solid connection and are water proof thanks to these

I bought the item worked when I melted it... the plastic made it tight/waterproof, but then the sodering part did not melt and the wires were connected, but then eventually disconnected, so I returned the case as it somewhat worked, but somewhat didn't its not a great item... 1 of the 4 units I used worked...