Kozy World Dual Gas Fuel Wall Heater Model KWD215, Vent Free - 12,000 BTU Fuel Type: Dual Fuel (Propane (LP) or Natural Gas) Thermostat - 12,000 BTU's Heating Area: 500 sq ft - Radiates heat providing direct, immediate warmth ODS, oxygen depletion sensor, safety feature Intended for indoor use only. Not designed for use in a recreational vehicle.