Mr. Heater, Corporation, 30,000 BTU Vent Free Radiant Natural Gas Heater, MHVFRD30NGT 30,000 BTU Natural Gas heater to heat spaces up to 750 sqaure feet. Radiant heat burner Automatic low oxygen shut-off system (ODS). CSA Certified Operating this heater at altitudes over 4,500 FT above sea level could cause pilot/ODS to shutdown the heater. Theromostat, legs and wall mounting hardware included