Cork/Rubber or "Crubber" as we like to call it, is a composite material made by grinding natural cork and rubber into small particles and then combining the two materials under pressure to form a tough, grippy material. 

Crubber is our go to non-slip material for lining vise jaws, but it has lots of other uses around the shop.  We use it as a pad on our sanding blocks, to create a grippy surface to hold thin smal material while planing, and to line the surface of clamping cauls.  There are literally hundreds of uses.