... 0.4~0.6 W/(m2 *°C)Hail resistanceØ25 mm 24mm Premium Heat Pipe Performance and Specification:Heat pipe materialOxygen ... pressure(Mpa)0.6Temp. Control(C)30-95CCopper coils size(mm)12mm/16mm/19mm,optionalHeat exchanger materialCopper, stainless steel, optionalFree components ... , SRCC, and CE &ISO. The Pictures about the Product : calentador de agua solar (SOLAR KEYMARK,SRCC certification)