Product review (1 stars): did not work, even with high amperage USB charger
This simply did not cool the interior, or a can of soda on the baseplate in the interior.  Using a meat thermometer, the interior air temperature was not much different from the outside.  I duct-taped a meat thermometer to a small (half-sized) can of soda, and left it inside for an hour, in contact with the aluminum baseplate: I could get only a 5 degree drop from ambient temperature.  Considering that that USB power source may have been limited to 500 miliamps (typical), I then tried a 2.1 amp 5 volt USB charger, with only a slight improvement, but still with less than 5 degrees temperature drop.  The interior baseplate seemed to feel cool, and can attract condensation, but that was about all it did.  Peltier chips tend to do better with somewhat higher voltage power supplies, and are not particularly efficient.  The larger 12 volt peltier coolers have insulation (this has none), a door gasket (this has none) and use far more electricity than a 5 volt USB power supply can provide.