AQUAH Outdoor Open Flue Liquid Propane Gas Tankless Water Heater 6 L / 1.6 GPM Brand New AQUAH outdoor open flue liquid propane gas tankless water heater Automatic electrical pulse ignition with no standing pilot, operated by 2 D Batteries; 85% thermal efficiency, 12,000 Watt / 40,900 Btu/h thermal input, ultra low startup water pressure; 45 dgrees temperature rise at the flow rate of 1.6 gllons per minute (GPM); Gas Pressure: 2800Pa (0.41 psi), free shower head with On/Off Switch.