40 Gallon, Natural Gas Water Heater, 40,000 BTU's, 1" Insulation, First Hour Rating 70, 41 GPH At 90 Degree Rise, For Installations From Sea Level To 10,100', R-Value 8.00, EF.62, Draft Diverter Outlet Size 3" With Integrated Adapter For 4" Vent Option, Factory Installed T & P Valve, FVIR Approved, Stainless Steel Flame Arrestor, Air Intake Entire Base Of Heater, Door Mounted Manual Reset TCO, Unit Dimensions 61-3/4"H x 20"D, 12 Year Tank & Parts Warranty, Not For Use In Mobile /Manufactured Homes, Models Built After 04-01-2011 Have Self Powered Honeywell Millivolt Generator Gas Control Valve.