This 3:1 heat shrink is high quality Polyolefin. Great for insulation, strain relief, and bundling. More versatile than 2:1, and thicker walled when drawn down. Draws down at 212°F (100°C). Operating temps from 275°F down to -67°F. Exceeds SAE AMS-DTL-23053/5 (class 1&3), and UL 224 VW-1 / CSA OFT specs. Priced and sold per foot (0.305 meter).