Yellowstone flameless cook flask 400ml black description this 400ml flameless cook flask is ideal for outdoor enthusiasts mountaineers backpackers hikers campers scouts and guides it creates a hot meal with the minimum of fuss and in safe conditions heat and cook food using the water activated heat pack it uses no gas or petrol to create heat making it far safer and simpler than other current cooking methods can be used inside a tent or confined space as it produces no carbon m