I'd like to try the GMK covers sometime. For now the heat shrink I have has been on since January this year. But it is HEAVY DUTY. It doesn't really shrink. When heat is applied the inside diameter expands, grows inward. The outside does slightly shrink but not much. Also on the inside is adhesive which sticks good. It's weird but this stuff ends up being 1.8mm thick, measured with calipers. It's really thick. The one problem I had was when I first put it on. I used too long of a piece and it grinded the rear diff around the pinion bearing. The heat shrink looked like I had just put it on, but the pinion, bearing, and diff case were toasted. So I use a tiny sliver now to just cover up the cvd pins.