Noritz® Tankless Water Heater, Mid Efficiency, Series: NR501, 15000 to 120000 Btu/hr Heating, Natural Gas, 1/2 in Gas Connection, Direct Electronic Ignition, 0.5 to 5 gpm, Energy Factor: 0.81, Copper Heating Element, Wall Hung Mount, 3/4 in Water Connection, 15 to 150 psi, 115 to 140 deg F, Ultra Low Nox: No, Indoor/Outdoor: Outdoor, Beige, 20.5 in H x 13.8 in W x 6.7 in D, Commercial/Residential/Dual: Residential