For making mid-morning tea out in the field! 
Also known as a Storm Kettle, and offered by Lehman's and by KellyKettle.com (UK)
The hollow kettle, made of double skinned aluminum, surrounds the fire you build in the base. The water absorbs the fire's heat in an amazingly efficient manner. Add fuel (paper, leaves, sticks, wood) through the 2"OD vent on top. Boil 40 oz of water in 3 minutes. Cork on brass chain can be inserted to keep water hot or from splashing out while in transit.