Vacuum Tube Solar water heater: CE certified, high efficiency, TIG welding, easy installation, reliable quality, good finish. ... stainless steel CE certified, high efficiency, TIG welding, easy installation, reliable quality Solar Water HeaterVacuum Tube: Dia. 47/1500, ... Dia.: 310mm, 360mm, 500mm;Inner tank welding: Double sides argon protection welding. No corrosion;Outer tank shell: Stainless steel ...