1.Windproof,antifrozen 2.Good design math your building 3.Long warranty 4.Antifrozen,heat resisting 5.Enjoy hot water Futures:1.Module of merterial1). inner tank: stainless steel SUS304/2B,food grade2). outer tank: galvanized / colour steel (milk white),alumium,or stainless steel3). frame: galvanized steel 4). insulation: polyurethane frothing5). vacuum tube: Al/N coating,47X1500 / 58X1800mm6). ...