If you rent an ultralight backpacking stove, you need to buy one of these clean burning butane and propane mix flat fuel tanks. 75% butane and 25% propane provides a great combination for cooking in the wild. With 100 gr. capacity, this tank burns for one to two hours depending on how you use it and at what elevation. This fuel can be used at high elevations and below zero temperatures. Remember to buy your backpacking food here.