(1) Unplasticized Polt (Vinyly Chloride) (PVC-U) Pipes for Water Supply ; (2) Unplasticized Polt (Vinyly Chloride) (PVC-U) Pipes for Low-Pressure Conveyance in Irrigation. PVC-U Pipe is divided into two kinds: (1) Unplasticized Polt (Vinyly Chloride) (PVC-U) Pipes for Water Supply: Diameter:...