1.All certificate solar collector 2.OEM service solar collector 3.High quality,low price 1.Bigger condenser,bigger radiator area,more efficient solar collector.2.Also bigger diameter of manifold,42mm or 38mm.SpecificationsActual ReadingsType of collectorHeat pipe pressurized,24mm condenser solar collectorInsulation materialRock wool,56mmDaily efficiency75%Type of liquidWater or anti-freeze ...