Material:Made of Polyolefin, Shrinkage Ratio:2:1 (will shrink to 1/2 its supplied diameter) Suitable for electrical insulation, wire bundling, colour coding, mechanical protection, wire/cable joints and daily repairs etc. Comes with 60pcs heat shrink tube assorted in plastic box, 6 colors( Yellow, Blue, Black, Green, Red,White). SHRINK QUICKLY, DURABLE and EVENLY-This shrink tube is well made of high quality material, thick and durable. Cover the area with them and shrinking them with a heat gun, then the wire shrink wraps will wrap the wire tight and evenly within 10 seconds. With this heat shrink tubing kit you will become more confident in your soldering work. EASY TO USE-You can just shink the shrink tube with a lighter or hair dryer when you don't have a heat gun on hand. Of course, if you'd like to use the heat shrink tubing kit more professional, standard heat gun will be much better lol. The wire shrink wraps are all pre-cut into the most common sizes you'll need which makes your work a lot faster.