RAYCHEM NETM1000 Heat Shrink Tubing is designed for reliable abrasion protection in HVAC systems. Made of durable black polyolefin, this single wall tubing has a 10mm [.39 in] inner diameter, perfect for insulating and safeguarding wires and cables. Each box contains convenient lengths of tubing, making installation quick and easy. With a high shrink ratio, this tubing ensures a tight, secure fit, even in tight spaces. Trust RAYCHEM NETM1000 for superior heat shrink protection in your HVAC applications.