... vacuum tubes and spare parts for free Integrated Pressurized Solar Water HeaterSpecification:inner tank: food grade sus304-2B ... hail resistance: 25mmOptional: heat exchanger (red copper), electric heater (1.5kw, 2kw, 2.5kw, 3kw), assistant ... :Working with high pressure, so do the water it produces.It uses the heat pipe to ... occasional tube breakage. Parameter Compact Pressurized Solar Water Heater