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 530pcs: 80pcs 1.5mm, 160pcs 2.0mm, 60pcs 3.0mm, 100pcs 4.0mm, 30pcs 5.0mm, 20pcs 6.0mm, 20pcs 8.0mm, 60pcs 10.0mm 5 colors: red, green, blue, yellow, black 70°C minimum shrink 125°C full shrink 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.