solar water heater : certification:ISO9001,ISO14001,CCC,CE,Solar Keymark solar water heater:heat pipe tube pressure:pressuriz model:integrated pressurized solar water heater:material:1.volume of storage tank:120L,180L,240L,300L2.pressurized water tank: insulating layer,polyurethane foaming ,thickness:55mm outer shell of tank,fluorin titanium plate,thickness:0.4mm inner tank,stainless steel SUS304 ...