Reliance Water Heater, Inlet Connection Size: 3/4 in, Outlet Connection Size: 3/4 in, BTU Rating: 40,000 Btu, Gas Type: Natural Gas, 72 gph, Tank Capacity: 40 gal, Energy Efficiency: 0.55 %, Recovery Rate: 43 gph, Vent Size: 3, 4 in, Water Connection Location: Top, Tank Height: 62 in, Emissions: Ultra-Low NOx, Dimensions: 18 in Dia x 62 in H x 18 in W x 18 in D