HSTT Dry Heat Shrink Tubing & Sleeves Panduit HSTT Dry Heat Shrink Tubing and Sleeves are designed with Polyolefin cross-linked material for impressive thermal, physical, and chemical resistance. These heat shrinks are flexible, flame retardant, UV resistant (black only), and feature an impressive 2:1 shrink ratio. The HSTT heat shrinks are RoHS-compliant, CSA-certified (except clear), and UL-recognized. Applications include strain relief, insulation, protection, bundles, color-coded wires, and electrical components.