Vacuum Tube Solar water heater: CE certified, high efficiency, TIG welding, easy installation, reliable quality, ... , high efficiency, TIG welding, easy installation, reliable quality Solar Water Heater Vacuum Tube: Dia. 47/1500, Dia. 58/1500, Dia. 58 ... steel, Al-Zn zinc steel sheet, or Anti-corrosion Fluorine carbon steel plate;Outer tank Dia.: 420mm, 470mm 600mm;Insulation material ...