... Vacuum Tube Solar water heater: CE certified, high efficiency, TIG welding, easy installation, reliable quality, good finish. Super stainless steel CE certified, high efficiency ... Dia. 58/1500, Dia. 58/1800, Dia. 70/2000;Vacuum tube qnty.: 12pcs, 15pcs, 18pcs, 20pcs, 24pcs, 30pcs, ... tank Dia.: 310mm, 360mm, 500mm;Inner tank welding: Double sides argon protection welding. No corrosion;Outer tank shell: ...