solar thermal collector,25mm Hail Resistance Includes Vacuum Tubes, Heat Pipes, Manifold, Frame,Silica Gel. solar thermal collectorSpecifications: Manifold: Interior: red copper with 1. ... 25mm Insulation: polyurethane/rock wool Optimal installation angle: vertical: 30 to 70 degrees Pressure drop: 7bar, 3.3L/minute for 20 ... products detailed description,pricing and service.Please send mail to us!