Unlike normal heatshrink these PTFE heatshrink tubes provide rugged insulation for wires on heatsinks and survive cryogenic cycling well. We often use this heatshrink to make miniature moulds for encapuslating wiring on our range of circular connectors. The heatshrink is shrunk onto a positive former, cut to length, then slipped over the back of the connector before the epoxy encapsulant is injected.