18 Tubes,150 L Evacuated Solar Water Heater 1.SRCC,Solar Keymark.SGS, 2.100000Btu ... Heat Preservation time: 72-96hours 10. Hail resistance: 25mm 11. Inlet/oulet size: 1/2'', 3/4'' 12. ... years for vacuum tube Lucky Non-pressurized Solar Water Heater Solar hot water specification: 1. Inner tank: 0.4mm-0 ... Heat Preservation time: 72-96hours 10. Hail resistance: 25mm 11. Inlet/oulet size: 1/2'', 3/4'' 12. ...