Duluth Forge Vent Free Dual Fuel Set-30 in. Berkshire Remote Control Gas logs, Stacked Oak 33,000 maximum BTU heats up to 1,300 square feet of living space Patented dual fuel technology operates off natural gas or liquid propane Minimum firebox size required: 20H x 34W in front (23"W at rear) x 15D LCD screen with remote control displays Remote controlled unit features O.D.S. (Oxygen Depletion Sensor) safety assurance with automatic shut-off function