... Water strong and pithiness, make you feel comfortable . 4.Water heater system is controlled by microcomputer, suit timely opened factory, school ... integral foaming, superior heat preservation. 7.Temperature when exposed to sun without water: 250, 2.5 hours to boiling if using ... : =93%, thermal radiation rate: 6% (100). 9. Optional Electric Heater: 1500w/3000w. 10.Resist 25mm hail, using life can last ...