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

I bought these after trying to rewire a trailer- replacing all of the lights. I started and got about halfway through and got sick of soldering and then using heat shrink tubes etc to join wires. I saw this product as my brother had a kit of these and it literally takes 20 seconds to not only connect wires but also watertight seal them. So far so good and my trailer is working like a charm. The first half of the trailer took me 1.5 hours, and then second half took around 15 minutes- it makes it so simple. I also installed a new car stereo in my daughter's vehicle and these were versatile enough that I could find connectors that were much smaller than what I used on the trailer wiring. I was able to join many different wires in minutes, and I am confident that it will stay joined better than the twist connectors I always used previously. You can either use these with a heatgun or a targeted lighted- but basically you have to get it hot enough to melt the solder in the middle of the connector- when that melts it creates a seal, and then the outer plastic tub shrinks to create a nice seal (also cosmetically pleasing- much more than the twist connectors.) I have seriouslly loved having these around and plan to use them consistently on my audio projects or low voltage projects in the future!

They melt at perfect temperatures and even if you over do the heat they still don’t break apart like the cheap ones but instead makes them bond to the wires insulation better. Surprised with how great

I like this product very much but has only couple problem. It's great to use on new wire, but when used on old wire it does not hold without some prep on wire. You will have to do some sanding or soldering flux. The other problem is if trying to do three wires. You cannot get two wires into one end without going to next size connection then cannot hold and melt solder because connection too big to hold wire tight to solder.

I always wanted these since I first saw them, they didn't disapoint.After 1 or 2 go's they work perfectly.a must for a diy home job or car work .

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.