Disappointingly bad. I wasted many of these trying to get one good connection, and not one worked properly. I tried a variable heat gun and a butane pocket torch, on multiple settings. No luck. I tried heating very slowly, only on the solder, solder first, then sleeve, sleeve first then solder, no luck. In every case, the heat required to melt the solder was way more than it took to melt and destroy the shrink sleeve.In fact, on most of my attempts, I watched the sleeve just drip away and leave See full review