SWFR tubing from TE Connectivity (TE) is cost effective, highly flame-retardant; 2:1 shrink ratio tubing made irradiated, cross-linked polyolefin. It insulates and mechanically protects components, electrical connections, and terminations. SWFR tubing from TE Connectivity (TE) is cost effective, highly flame-retardant; 2:1 shrink ratio tubing made irradiated, cross-linked polyolefin. It insulates and mechanically protects components, electrical connections, and terminations.Heilind Electronics, Inc. (www.heilind.com) is one of the world's leading distributors of connectors, relays, switches, thermal management & circuit protection products, terminal blocks, wire & cable, wiring accessories and insulation & identification products.