Black dual wall polyolefin heat shrink tubing with a 1/2'' nominal diameter is made from polyolefin. It's stable, flame retardant, and the extra thickness provides excellent abrasion resistance. Contains an adhesive which flows when heated to create a permanent and water tight environmental seal. Has a 3 to 1 shrink ratio. Operating Temperature of -67F to 248F (-55C to 120C). UL listed and CSA certified.