... double-wall corrugated pipe of all types, HDPE (from type DN20 to type DN1200) water supply, gas supply pipe, PP-R Jiangsu ... 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 floor heating pipe and ...