... :ASTM,DIN,UNI,GB 2,Galvanized 3,Material:low carbon steel tube 4,Use:car, refrigerator O.D(mm) Thickness(mm) 3 ... .180.7 4.000.7 4.760.7 5.000.7 6.000.7 6.350.7 7.940 ... ,GB3,Material:low carbon steel tube4,Zinc plated5,Wall thickness:0.5mm~0.7mm6,Outer diameter:3.18mm~12mm Galvanized bundy steel tube