... ok Cheapest & Efficient Chinese Solar Hot Water There are mainly 3 kinds of flat solar collectors with different coating1, ... 2, Blue Titanium Sputtering series: absorption:~95%, thermal emission:~5%3, Anode oxidaiton coating series: showing as belowSTANDARD SPECIFICATION:Absorber coating: selective ... profile: EPDMConnection: Ø22/25mm Gross /Aperture area: 2 sqm / 1.85sqmGross size: 2000mm*1000mm (L*W ...