If you read the last comment on the page, it sounds like they might be hard to come by.

There is somethign similiar that I've seen places like Brigade Quartermaster in the recent past, called Heat Cell. Might be the same thing, or something very similiar, but I think it only had a 20 minute burn time. But that does sound a little more realistic than the 80 minutes given by Brunton.
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-IronRaven

When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.