SUPER easy to use! I don't know what's up with the negative reviews. Maybe they don't know what they're doing, but as long as you keep the heat moving, it's pretty hard to screw up. I got these to work with a bbq grill lighter, so you should be able to do this even easier with a small propane lighter or a B1C or anything with a controllable flame. Just let the flame lick the surface while moving back and fourth and the solder will change from shiny silver to dull gray and the heat-shrink will close in on it. Let is sit for a solid 30 count then pull test it. I just did 8 splices like a pro with these and didn't have a single screw up at all. These even have a moisture seal making them completely waterproof, so you can use them on wires that are exposed to the elements without worry. Very nice!If this review was helpful, please click so below. Thanks :)