Commercial Gas Water Heater, Fuel Type Natural Gas, Low NOx Yes, First Hour Rating 264 gal, Gas Inlet Size 3/4 in, Maximum Heating Capacity 199,900 BTU/ft/sq ft/hr/ Degrees F, Overall Height 73.06 in, Tank Diameter 30.25 in, Included Valves Temperature and Pressure Relief, Tank Capacity 100 gal, Hot Outlet Size 1 1/2 in, Maximum Recovery Flow Rate 485 gph @ 40 Degrees F, Market Commercial, Vent Type Standard, Features Full Port/Full Flow Brass Drain Valve, LED Diagnostic System