... and 15 years for vacuum tube.Non-pressurized solar energy1.solar water heater with CE,3C,ISO9001,CNAL certificate;2 ... *1800mmAccessories: MG rod, electrical heating, assistant tankLogo: OEM, co lour printing /stickerFeature: 1.Solar water heater with CE,CCC,ISO ... heat transferring and long life span of the solar water heater4.Exquisite workmanship to guarantee the decent appearance5.Certificate ...