This is the most substantial, thick heat shrink I've ever used. It does shrink pretty far (didn't test the ratio precisely), and is crystal clear when shrunk. It also shrinks up to be super thick - I got this mainly to put labels on cables, but it's so nice and thick I've used it for other things that could benefit from durability (trailer wiring for instance). Shrinks up to be about 1mm thick, I'd guess.