Mr. Heater Big Buddy Portable Heater - The Most Popular Portable Propane Heater in North America. This patented radiant 4,000-18,000 BTU Liquid Propane heater connects directly to two 1 lb. cylinders and is the perfect solution for heating enclosed spaces like cabins up to 450 sq. ft. Two swivel regulators give you the ability to adapt usage from disposable cylinders to a remote gas supply with the purchase of a single hose and filter. To light the unit, simply push and rotate the knob. The built in Piezo sparking mechanism will take care of the rest. With the Oxygen Depletion Sensor (ODS) and accidental tip-over safety shut-off, you can be sure that you will enjoy years of comfortable indoor safe heat. 4,000 BTU, 9,000 BTU or 18,000 BTU per hour For use with propane gas Heats up to 450 sq. ft. Single control start knob Hi-Med-Low heat settings Swivel regulators Automatic low oxygen shut-off system (ODS) Accidental tip-over safety shut-off Connects to two 1 lb. cylinders Connects to a 20 lb. cylinder with optional hose