Product review (5 stars): I use this for my medicine.
I use this for meds that I have to keep cold.  It cools it from a metal plate on the bottom.  Ideally, you have a can of soda in there and the metal from the can cools (or heats) the entire cup.  It works well for my medicine at keeping it cool.  I've also used the heating option to keep drinks warm as well.  Pretty cool device.