Product review (4 stars): Works but not great
This little fridge is just a little peltier cooler. It only cools the bottom of the can. There is no insulation in the "fridge" because the entire thing doesn't get cold, only the base.

It would be great if they had something like this that was a compressor so the entire box got cold but that would be expensive, loud, and wouldn't run on USB.

I haven't tried the heat setting, only the cold setting. It does take a while to chill a can, approximately 2 hours to go from room temperature to ~50F (the temp I like to drink at). It is meant to keep already cold cans cold longer.