Mr. Heater Corporation F299711, Corporation, 10,000 BTU Vent Free Blue Flame Natural Gas Heater, MHVFB10NG 10,000 BTU Natural Gas heater to heat spaces up to 250 sqaure feet. Blue flame burner for even convection heat. Automatic low oxygen shut-off system (ODS). Operating this heater at altitudes over 4,500 FT above sea level could cause pilot/ODS to shutdown the heater. Legs and wall mounting hardware included