... 5 years for whole system and 15 years for vacuum tube.Non-pressurized solar energy1.solar water heater with CE,3C,ISO9001,CNAL ... : MG rod, electrical heating, assistant tankLogo: OEM, co lour printing /stickerFeature: 1.Solar water heater with CE,CCC,ISO ... after installation7. Easy opearationSpecification:Inner tank: stainless steel SUS304/2B, 0.41mmOuter tank: galvanized/ co lour steel, ...