Solar water heater 1.certification:ISO9001,ISO14001,CCC,CE,Solar Keymark 2.solar water heater:heat pipe tube 3.pressure:press Solar water heater: material:1.volume of storage tank:120L ... :12bar3.dust ring gasket :EPDM4.evacuated tube:three-target tube,high boron and silicon,content 3.3,structure,gradual change SS ...