Automatic thermostat, 99, 9% efficient, Built-in Oxygen Depletion System (ODS), No electricity required, Matchless piezo ignitor, Wall mount, Optional floor stand and blower available by special order, Not for high altitude, 20,000 Btu/Hr, Size: 18"" W x 23-1/2"" H x 8"" D, SKU: HMREX533