Indoor-safe portable propane heater for rooms up to 95 square feet. Continuous odor-free, 45-degree heating angle. Maximum Elevation (Ft) 7000 Feet. Automatic low oxygen shut-off system (ODS). Simple on/off buttons; uses 1-pound disposable propane cylinder (not included). Run time at minimum btu and maximum btu is 5.6 hours. Do not operate heater in any moving vehicle. This heater requires a vent area of 4 square inches minimum for adequate ventilation during operation. It has a low-oxygen sensor and accidental tip-over switch with auto shut-off for safety. Recommended for emergency heat, tents, campers, workshops, job sites, porches, patios, decks, garages, storage buildings, picnics, tailgate parties, construction trailers, sporting events, barns, sheds, hunting blinds, shelters and ice fishing shanties.