This Blue Flame 10,000 BTU Dual Fuel Vent Free heater (Model # MHVFDF10BF) is the perfect supplemental heating solution even on the coldest days. Operates on either Propane or Natural Gas, with easy Piezo Ignition, and heats up to 300 sq. ft. Designed with absolute safety in mind, Mr. Heater’s patented vent free dual fuel system is composed of dual valves and dual oxygen depletion sensors and includes a manual selector switch to ensure correct installation. Unit can be permanently mounted to the wall, or securely fastened to the floor with included mounting brackets and fasteners. Clean burning blue flame tube burner uses the natural convection of the burn to circulate warm comfortable air. Dual LP/NG low oxygen detection systems Fail safe fuel type selector knob Battery operated electronic spark ignition