... demension 2.Surface:galvanized,paint... 3.Section:square,rectangle, 17x17x1.2mm Square Hollow Section tube1.Size:specified demension 2 ... .Surface:galvanized,paint,annealed etc. 3.Section: square, rectangle, ellipse, semicircle, arch, sector, triangle ... Thickness: customized (from1.0mm-20mm)3-Length: customized ( 3m/5.8/6m usually)4-Section: square, rectangle, ellipse, ...