Product Description: Have you ever struggled with the unsightly and unsafe nature of wrapping cable and wire connections with electrical tape? The good news is that our heat shrink tubing avoids these hassles and makes your connections cleaner and more aesthetically pleasing! Heat shrink tubing can be used as an insulating waterproof cover for exposed wires. It can be used for low voltage maintenance in wet areas, outdoor electrical equipment, welding protection, reinforcing headphone and cell phone charging cables, repairing LED filaments, remote control aircraft and vehicle maintenance. It will meet your needs and it won't hurt to buy more for your home. How to shrink waterproof casing? 1.Select the appropriate size heat shrink tubing, no more than 3 times the diameter of the wire. 2.Cut the heat shrink tubing to the desired length. 3.Wrap the cable wire around the heat-shrink tubing, heating it with a lighter if the tubing is small, or with a hairdryer or heat gun if the tubing is large, until the cable wire is tightly wound. 4.Be careful not to touch the tubing until it is cool, beware of burning your skin. Specification: Material: Polyolefin Heat shrink ratio: 3:1 Operating temperature: -55 degrees Celsius to 125 degrees Celsius Shrinkage Temp: 212 degrees F Full Shrinkage Temp: 230 degrees F Max Tensile strength: 10.4 Mpa Dielectric strength: 15 kV / mm Package included: B style: Box of 135PCS Red 20pcs 6.5cm length, Diameter: 6.4mm 25pcs 3.8cm length, Diameter: 12.7mm 20pcs 3.8cm length, Diameter: 19.1mm 30pcs 3.8cm length, Diameter: 9.5mm 20pcs 3.8cm length, Diameter: 15.4mm 20pcs 3.5cm length, Diameter: 25.4mm