... Surface finish:Hot dipped galvanized Standard:GB/T3091-2001,BS138 Out Diameter: 10.3mm - 406. ... , EN10219, ASTM SCH40, ASTM SCH80\Surface Finish: hot dipped galvanized, electro galvanized, blackOut DiameterWall ThicknessLengthInchmmmmmeter1/2"21.3mm0.6mm-3.0mm0.3m ... .0m16"406.4mm8.0mm-20.0mm1.0m-12.0mNote: Pre-galvanized round hollow section with OD 19mm-100mm and thickness 1mm ...