30 Gallon, Natural Gas, Short Water Heater, 35,500 BTU's, 1" Insulation, First Hour Rating 60, For Installations From Sea Level To 10,100', R-Value 8.00, EF.61, 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 Surrounds The Entire Base Of Heater, Door Mounted Manual Reset TCO, Unit Dimensions 50"H x 18"D, 6 Year Tank & Parts Warranty, Not For Use In Mobile/Manufactured Homes, Models Built After 4-1-2011 Have Self Powered Honeywell Gas Millivolt Generator Control Valve On Units.