... quality, good finish. The following are the features of our vacuum tube solar water heater:CE certified, high efficiency, reliable quality ... tank TIG welding, super stainless steel, easy installation, competitive price.Vacuum Tube: Dia. 47/1500, Dia. 58/1500, Dia. 58 ... welding. No corrosion;Outer tank shell: Stainless steel, Al-Zn zinc steel sheet, or Anti-corrosion Fluorine carbon steel plate ...