Duluth Forge Vent Free Dual Fuel Set-18 Remote Control Gas logs, Split Red Oak 30,000 Maximum BTU heats up to 1,100 square feet of living space Patented Dual Fuel Technology operates off natural gas or liquid propane Minimum firebox size required: 20H x 29W in front (22W at rear) x 13D U-Burner chassis design, with black powder coating, provides two rows of flames to create a realistic fire Remote controlled unit features O.D.S. (Oxygen Depletion Sensor) safety assurance with automatic shut-off function