These are the beez knees when it comes to weatherproof joins. I’ve seen these in horrific corrosive wet environments last perfectly compared to solder joints.You MUST heat them evenly until the glue comes out and cable must be clean.ALWAYS tug test your crimp after crimping. Good product, should be cheaper for bulk buys.If you ever want to seal off a cable. You can use pliers to heat, glue and then close off the open end.

While searching for shrink tubing I came across these which have it simpler than separate crimps, then cutting the wire because I forgot to put the shrink tube on first, then doing it correctly the second time. Admit it, you know what I mean & you've done the same. They do not seal as well as a waterproof double layer shrink tube, but they've survived a year outdoors in Florida rain storms & the crimp is holding the wires together with lightweight string lights hanging a 3ft droop between supports so far.

Works great. These butt splices stay in place no issues.

Butt splices with heat shrink insulation are the only way to go. When properly sized to the wire and properly crimped, this connection is just as strong as the wire itself The heat shrink not only seals the connection, but reinforces it also, whereas a normal butt splice is only held together by the crimp itself. Short of Deutsch connectors, this is the only thing I will use.