... Description: Solar tank : Avaliable Capacity: 100L,120L,150L,200L,250L,300L,400L,500 L.,600L,700L,800L,1000L,1200L Inner tank : SUS304 ... - food grade stainless steel . Outer tank ... steel. Insulation layer: 60mm polyurethane foam. Heat exchanger in tank : copper coils/stainless steel coils. Heat preservation: 72 hours ...