... SOLAR WATER HEATING, EVACUATED TUBES, VACUUM TUBES, HEAT PIPE SOLARWATER HEATER, HEAT PIPE SOLAR COLLECTOR, SOLAR PANELS, SOLAR COLLECTOR, ... PANELS, WATERHEATING, SOLAR COLLECTOR WINDOWS,SOLAR HEATING COLLECTORS Heat pipe solar collector1.Anti-frozen & pressurized system2.Special ... 20pcs.25pcs.30pcs, 40pcsTube hail resistance:≤25mm Certificate for Heat pipe solar collector :CE ,ISO .SOLAR KEYMARK , ...