erw steel pipe 1)OD: 21.3 - 609.6mm 2) WT: 2.5 - 19.1mm 3) Standard: API SPEC 5L, ASTM, ... BS, GB/T9711.1-1997 erw steel pipe1:erw steel pipe1 ... 24")2) Wall thickness: 6 - 19.1mm3) Standard: API SPEC 5CT2:Line pipes:1) Nominal OD: 114.3 - 609.6mm (4" - ... API SPEC 5L, ASTM, BS, GB/T9711.1-1997 3:Low pressure liquid pipe:1) Nominal OD: 21.3 - 194mm (1/2" - 7 1/4 ...