TIL those exist. I assume they use a low melting point solder, that melts at about the same temperature that the tube shrinks. Seems a lot more convenient than the usual - soldering, finding out that you forgot to put the heat shrink tube on first, desoldering, putting on the tube, soldering, tube shrank prematurely since the heat traveled along the cable, redoing again, finding out that the solder blob is too large to slide the tube over, removing some solder from it, sliding the tube over, heating, and done....