Vacuum Tube Thermosiphon Solar Water Heaterand Steel Powder Coated Stand Parts. With CE . ISO.OEM Vacuum Tube Thermosiphon Solar Water HeaterInnVacuum Tube Thermosiphon Solar Water Heaterer water tank shell: SUS304-2B food grade stainless steel plates Outer tank shell: color steel plates Welded by argon arc Water is pure and drinkable Heat insulation of water tanks adapts polyurethane foam and ...