For use in electrical systems to repair, insulate and add strength to wiring Tubes shrink to half diameter when heated to provide a secure seal Includes 127pcs: 30pcs 2.0x40mm, 25pcs 2.5x40mm, 20pcs 3.5x40mm, 20pcs 5.0x40mm, 16pcs 7.0x80mm, 8pcs 10.0x80mm, 8pcs 13.0x85mm 70°C minimum shrink 110°C full shrink -55°C to 125°C operating temperature bulk package, no box Use a heat gun or lighter at about 1/2 inch distance to shrink the tube. Don't touch the tube until it is completely cool.