... ,RoHS,CCC,CE 10years warranty Factory price Non-pressure Vacuum Tube Solar Water Heater Vacuum tubes assimilat the advanced 12 layers of apattering deposition of ... SS-C/CU selective complex absorptive coating. Through the interlayer, vacuum has an unique effect of thermo, with its temperature up ... heat zinc steel plateInstallation angle: 27°, 38°, 45° Non-pressure Vacuum Tube Solar Water Heater System