400x400 / 280x280 450x300 / 450x200 / 400x350 / 400x250 / 500x250 / 500x300 4.5MM -- 15.75 MM 6M IN STOCK (OR CUSTOMIZED) SPECIFICATION OF PRE-GALVANIZED HOLLOW SECTION TUBE: Square Hollow Section (SHS) WT(mm) Rectangular...