... ISO9001,CCC,CE,Solar Keymark 2.solar water heater:evacuated tube 3.pressure:non-press Solar new energy: material:1.volume ... pressurized water tank: insulating layer,polyurethane foaming ,thickness:55mm outer shell of tank,titanium fluoride ,thickness:0.4mm inner tank,stainless ... pressure:0.4bar,3.dust ring gasket :ABS4.evacuated tube:three-target tube,high boron and silicon,content 3.3,structure,gradual ...