Be prepared for your next wiring project with these Heat Shrink refill kits from Aeroflow Performance. Heat shrink tubing is a type of extruded plastic tubing that can be cut to size and fitted over a wire or cable joint to protect and insulate the connection. When heated is applied the tubing shrinks permanently providing a protective seal. These refill kits are designed to suit our AF49-8990BLK heat shrink kit or can be purhasced for individual jobs. Offering a range of pre-cut 4-1/4" long heat shrink with sizes varying from 3mm to 19mm. The 2:1 shrink ratio allows for a great seal to protect your wiring.