Professional Classic Atmospheric 50 Gallon Natural Gas Water Heater. Professional Classic Plus™ Atmospheric gas water heaters are engineered for more hot water at a low operating cost. Efficiency .63 UEF More hot water at a low operating cost Performance FHR: 51 - 87 gallons Recovery: 30.3 to 40.4 GPH at a 90° F rise, depending on model Guardian System™ & Sensor Exclusive air/fuel shut-off device Maintenance free – no filter to clean Protective control system that disables the heater in the presence of flammable vapor accumulation Low Emissions Eco-friendly burner, low NOx design Meets 40 ng/J NOx requirements Longer Life Premium grade anode rod provides long-lasting tank protection Plus… Easy to light – no matches required EverKleen™ patented system fights sediment build-up Enhanced flow brass drain valve Temperature and pressure relief valve included Low lead compliant Standard replacement parts. Product Info Specifications Dimensions Product Depth (in.) 23.75" Product Height (in.) 51.13" Product Width (in.) 23.75" Details Fuel Type Natural Gas UEF 0.63 Primary Warranty 6 Low Nox Yes Number Of Back To Back Showers 1 High Altitude Compliant Yes Tank Capacity 50FetchDocument.aspx?ID=13A26A10-A506-44F0-B83A-CAA58A875ED8FetchDocument.aspx?ID=80B1D50E-695F-49AC-9AAE-3E9489EF1E5A