non-pressurized solar water heater The CN-YS02 type has the stainless shell,so it can be used in the rain area ... water heater 1,vacuum tube length:47/1500mm,58/18002,vacuum tubes:15pcs,18pcs,20pcs,24pcs,30pcs3,Outer tank material:202stainless steel ... polyurethane thickness:50mm or 55mm6,Optional electric heater:220v-240v 1500w/3000w7,frame material :202 stainless steel8,we could product for customer ...