... efficiency 2,easyly installation, energy-saves 3,competitive price 150L compact non-pressurized solar water heaterNon-pressure Solar water heater ... preservation 5) Frame materials: Corrosion resistant stainless steel6) Type: 12, 15, 18, 20, 24, 30, 36tubes 7) Capacity: 100-350 ... . Vent connection(inch): 1/24. Electric heater connection(inch): 15. Water connection(inch): 1/26. Collector angle(degree): 30 ...