SOLOOP 381 Pcs Heat Shrink Tubing, 2:1 Shrink Ratio Assortment Wire Wrap Electrical Cable Tubing Sleeving (Black) Material: Made of Polyolefin, resistance to common fluids and solvents as well as high dielectric strength 2:1 Heat shrink ratio: When heated the tube shrinks to 1/2 of it's diameter and the adhesive lining melts and flows around the material being covered giving a permanent weatherproof bond Temperature: -55C to + 125C Suitable for: a wide range of applications, including electrical insulation, strain relief, cable bonding, color-coding and identification Packing : All packed in a plastic container for easy organization and storage.