Trident Polyduct Blower Hose, polypropylene, 4" ID, blue, sold by the 50' coil. Rugged blower duct hose for heat, ventilation and air conditioning. Heavy duty polypropylene hose reinforced with a flexible polypropylene rod helix. It has excellent flexibility and compressibility, excellent resistance to crushing, flex fatigue, tearing and moisture. Meets FMVSS 302 flame resistance. -40 to 225 deg F temperature range.