solar heater collector 1.CE mark 2.Adjustable frame,easy and safe to use and protects freezing 3.Good quality. solar ... steel(food class),0.4mm thickness 3.Vacuum tube:high quality borosilicate glass,AL-N-AL coating, ... steel,1.5mm thickness6.Hailresistance: 25mm diameterModel Vacuum Tube SizeCapacity AreaWater Tank DiameterVolumeLoading Quantity(sets)DiameterLengthQuantityOuter TankInner Tank20 ...