... ,structure:gradual change SS-AL-Nx/Cu selective absorption coating;life:15 year3.frame:aluminum alloy,thickness:2.0mm4.water tank:color ... term performance4) Light-weight - easy to transport5) Attractive design, standard frame suitable for pitched roof or flat roof6) Reliability and long ... .3,Structure,Gradual change SS-AL-Nx/Cu selective absorption coating,Vacuum Degree,P<=5*10-4,Service Life,10 years ...