... food-level stainless steel)4, Frame: painted steel or Aluminum Alloy or Stainless steel5, Frame gradient According to local latitude6, ... any other solar thermal products, for its most high efficiency, low cost, easy installation. Advantage1,The inner tank uses fully- ... prolong the life and resist corrosion; Anticorrosion inner tank, low maintenance cost.2,Superior heat preservation ensured by one-off ...