I wondered when somebody would consider using "other" forms of water, (personally 'passed' for quality :shock: ) however, if your son was snowmobiling, a metal canteen cup kept neat the engine, radiator or exhaust would heat snow sufficiently to activate an FRH, however, a couple of retorts kept nea...

thought this one was interesting:
http://cgi.ebay.com/BAGGED-NEW-CHINESE- ... dZViewItem
-Az

Great, now my wife wants to try one!