selling HDPE double-wall corrugated pipe of all types, HDPE (from type DN20 to type DN1200) water supply, gas supply pipe, ... selling HDPE double-wall corrugated pipe of all types, HDPE (from type DN20 to type DN1200) water supply, gas supply pipe ... , PP-R (from type DN20 to type DN160) cold & hot pipe, PE-RT ...