The Mr. Heater 18,000 BTU Portable Big Buddy Heater gives anglers adjustable propane heat for cold days in the ice shanty, fishing cabin, garage, workshop, or camp. Three heat settings provide 4,000, 9,000, or 18,000 BTU per hour, letting you match the output to changing temperatures while heating spaces up to 450 sq. ft. Swivel regulators connect directly to two 1 lb. propane cylinders, while an optional hose lets you run the heater from a 20 lb. cylinder for longer stays on the ice or at camp. A single control start knob simplifies operation, and the automatic low-oxygen shutoff system and accidental tip-over shutoff add important safety features for winter anglers chasing walleye, perch, crappie, and lake trout in cold conditions.4,000, 9,000, or 18,000 BTU heat settingsHeats spaces up to 450 sq. ft.Connects to two 1 lb. propane cylinders or optional 20 lb. cylinder (propane not included)Low-oxygen and tip-over safety shutoffsSingle control start knob for easy operationSwivel regulators simplify cylinder connectionsManufacturer's one-year limited warranty