Comfort Glow, Biltmore Split Oak 24" Yellow Flame, Vent-Free, Natural Gas Log Set, Dual Burner, Thermostat Operation Automatically Modulates Heater From High 39,000 BTU & Low 20,000 BTU Or Any Setting Between High Or Low To Pilot, User Selects The Heat Setting/flame Height By Simply Turning The Control Knob Which Provides Enhanced Yellow Flame Appearance, Hand Painted, Multi Colored Realistic Concrete Logs, Matchless Ignition, Oxygen Level Control ODS, System, Front Mounted Controls, Pressure Regulator, Vent Free Heaters & Hearth Products Not For Sale Or Use In California, Check Local Codes For Restrictions On Sale Or Use, Operating Heaters At Elevations Above 5,500' Could Cause Nuisance Outages.