... CCC and CE certified 3.Using wood stress ,quality assurance Flat solar water heaters 1).Heat collector machine size: Φ47--1500, Φ58--1800, Φ70 ... steel,Pearl board,White-color painted board,Galvanized steel plate(3).Inside water chest: imported BS SUS304-2B stainless steel (food class ... : 38 ~ 45.(6).Grade A material: imported hot zinc steel plate.(7).Falling water collection method.