Features 84 Thermal efficiency ASME code brass headers Built with heavy-duty commercial grade materials Natural gas or propane and hi altitude models Meets ASME, Low Nox requirements Unitherm Governor anti-condensation control Protective wire harness to prevent rodent damage 336, 000 BTU Electronic NG Heater - Cupro - Nickel Dimension - 31.75 x 30.75 x 44.25 in....