1.twin-glass evacuated tubes：Reliable, efficient, High temperature resistant anti-freezing. 2.There is no water in the vacuum tube, it can still work even one tube is broken. 3. U pipe, most efficient 4.aluminum alloy manifold and bracket, corrosion resistance, easy to install. It can be installed both on flat roof and inclined roof 5.more flexible Installation, installation angle from 0 degrees to 90 degrees, roof and wall hanging installation. 6.high temperature resistant rock wool / glass cotton insulating layer, high density, good thermal insulation properties. 7.high quality copper heat exchanger, it can withstand 1MPa. 8.Improves the environment and save your fuel cost. working principle: the vacuum tube absorbs solar radiation and transform into heat, pass to the fin by the tube wall, and then transfer to the U pipe by the fin, U pipe absorbs heat then transfer to medium, cold medium continuously flow into inlet and heated by U pipe, then flow out from the outlet, so that obtain the heat of solar energy heating water. http://www.sidite-energy.com