Review on Qiilu Waterproof Connectors Electrical Automotive by Trey Michaels

These are about the only small butt connectors you can get on this platform and they are heat shrinkable and they really are heat shrinkable but crimping them can be a challenge be. They are tiny and the insulation is so thick that sometimes it either slips off or gets in the way of proper crimping. Plan to crimp a few connections before you get the hang of it and find out which of your crimping tools works best. And yes, they do shrink, but not as much as regular heat shrink tubing.