PET+ (PET Flexible Duct) is a double-layer polyethylene agglutinated to the helix steel wire. It can be applied in the HVAC line ,with its durable character and low cost, it is popular all over the world. Diameter available from 4"-16" (100mm-400mm). Its standard length is 10meter, and it can be compressed to 0.2-0.4meter.