Would be nice to live in a region where this would actually be a useful product :)

It's usually not warm enough here, decent beer is sold in glass bottles, and in general I don't know what a single cold beer would get me over bringing a whole cooler full of beers.

Seriously, I wonder where one uses those. Where do you bring a single beer of your own instead of buying one, and where do you drink it so so slowly that it would warm up fast enough to justify 25$?