Gardner Bender heat shrink tube is insulated PVC tubing material. Each tube is very flexible and flame retardant. This PVC heat shrink tube is a great insulator for general wire splices terminals and other electrical connections. The polyimide adhesive in each tubing type below will melt and flow when heated with a heating torch encapsulating and sealing the components contained within and it also provides strain relief for electrical wire connections. Heat shrink tubing is great for cable insulation marking and bundling with superior mechanical abrasion and moisture protection. Polyolefin shrink tubing shrinks under heat application to insulate wiring up to half its diameter.