The big buddy blasts either 4000, 9000, or 18,000 BTU’s and is rated to an area of 450 sq. ft. It requires 2- 1lb propane cylinder. PROPANE IS NOT SUPPLIED, BUT AVAILABLE ALMOST EVERYWHERE. This past fall I had a Big Buddy with me on a full week-long trip brown trout fishing, boy was I glad I did. The weather turned out to be extremely inclement, for the duration of the trip. We had a mix of snow, rain, sleet, and wind every day. We had the Big Buddy sitting on the picnic table inside the Sugar Loaf shelter and even with 20mph winds, it did its job perfectly. We used it for everything from drying wet wool socks to warming our hands while we cooked. While these are fine in something large and vented like an EZ-up or Sugar Loaf, we DO NOT suggest you use them in ANYTHING fully enclosed, flammable, or unventilated. ESPECIALLY A TENT!!!!