Plumbeeze Fast Recovery Heat Shrink Kits are made of adhesive lined cross-linked polyolefin heat shrinkable tubing that is designed for applications up to 600 volts. The good abrasion resistance characteristics of this tubing provide excellent mechanical protection. When heated above 120°C (250°F)) there is a 4:1 shrink ratio. Upon cooling the adhesive solidifies, forming a permanent, non-drying flexible and waterproof barrier. Black tubing is flame retardant, clear tubing is not flame retardant.