Z-Block (100) 2” Wide x 60” Long, Clear Water-Blocking, Hot-Melt Tape to Waterproof Wire Connectors or Bundle of Cables, Perfect for Automotive Wiring

It's like shrink tubing in the sense that you heat it up and it shrinks around the wires. It's different in the sense that when you heat it up it sort of melts into all the nooks and crannies making the connection waterproof. Also, since it's a tape, you can apply it after the fact which you can't do with a tube. So far, so good. But, there are a couple of downsides. First, it's not adhesive, so you can't just wrap it around wires and have it stay so you can apply the heat gun. You either have to use a little piece of some adhesive tape to hold it in place or, what I do, is after I cut off a piece to use, I heat it up just enough to make it a little tacky and then quickly wrap the now tacky tape around the wires, then quickly, apply the heat gun until the tape melts. The other downside is that after it melts, it is pretty thin if you only wrap it once or so. So, you may either want to put on additional wrap, go around twice of more, or cover the melted tape with some other tape like use some thick self fusing tape (which is what I do). Obviously depends on the situation. If outside in the rain, I would use at least two wraps and then a wrap of fusing tape. Lastly, I would note that the melted tape and fusing tape is fairly permanent, not like just using electrical type or a goop filed wire nut. and yes, it is fairly expensive, so I just cut off a strip in the opposite direct. As an aside, what I would really like is thick fusing tape that would shrink down tight with heat. In theory, you use could some shrink tubing that has adhesive on the side (often used for marine battery application). Then cut it down one side so you can wrap it around some wires, then heat it up. I might try this. (just thinking as I write this - sorry). But, this tape is interesting.

Used to wrap aircraft cable ends. It shrinks and bonds nicely. Tough to get it in place as it is non-adhesive.

I used it on my welder whip to seal up bad spots in it , then covered with electrical tape

This tape is intended to be cut to fit into or around anything you want to encapsulate or glue together. Then when you heat the assembly with a heat gun the glue melts and flows into all the crevices or gaps. When it cools again the parts are very well bonded or encapsulated and the assembly stays strongly protected as long as the temperature does not again go up to 100 C. For us a great advantage is being able to fit pieces of this tape into small parts ahead of time, so later when the parts are put together they can be bonded and encapsulated without any fuss or mess, no mixing of epoxy, no delay waiting for glue to cure, no clean-up, no worry about shelf life, pot life, or mixing ratio. A great product.