... , thickness1.2mm,1.5mm,2.0mm. Water purity for drinking.Outer tank materialColoured plate,galvanized steel, stainless steel(optional ... grade steel, anti-corrosion 1) inner tank : imported SUS-204 stainless steel 2)outer water tank: stainless steel , colored steel, galvanized ... steel 3)capacity: 200, 250 ,300,400L 4)tank diameter:410, ...