Joule Stove Grey. Award-winning group system providing liquid fuel performance. Ideal for alpinists, the Joule is made for the most extreme conditions. Its inverted fuel can and liquid feed regulator provide the performance of a liquid/multi-fuel stoveâ??with the ease and versatility of a canister systemâ??offering consistent heat output down to 10Â°F/-12Â°C. A 10,000 BTU burner provides raw power for rapid boil times with excellent simmer control for cooking, while the 2.5 L insulated FluxRing vessel offers the fuel efficiency, portability, easy-setup and the reliability you need.