Descriptin: Vacuum tube:58-1800mm high borosilicate 3.3 glass vacuum tube with tube wall thickness of 1.6mm. Inner tank material:SUS304-2B Stainless Steel with thickness Outer tank material:Stainless steel Frame material:Stainless steel with thickness of 1.5mm Capacity of water tank:200L, 240L, 300L, 360L Cooper coil:With dia of 12mm and wall thickness of 1.0mm Cooper coil length :200L for 30m, 240L & 300L for 35m, 360L for 40m. Heat preservation layer:High pressure automatic Polyurethane foaming layer with thickness of 55mm Heat preservation hours:48-72 hours Hailstone resistance:Diad25mm Optional accessories:Electrical heater