Review on Sopoby'S Waterproof Solder Connectors - Complete 140PCS Kit For Marine, Automotive And Home Wiring by Sean Young

I've used this type of solder heat shrink connector (different brand) in the past and they were not this difficult.These are very finicky to use. Easy to split the shrink wrap before the solder melts. I started out trying to use my heat gun (1800w adjustable). But could not get the solder to melt enough to actual hold the wires together. Moved on to the trusty torch. This is where patience and using something else besides your have to hold the wire. I found that if I hold heat far enough away and try to focus the heat on the solder portion that I could get the solder to break before splitting the shrink wrap and/or catching the wire shielding on fire. I have a good 95% effective rate with this method. The solder isn't completely melted as it should be but for what I will use these on, it's enough to make it work and seal the connection.