Product review (1 stars): Gimmick, avoid it
The rocker switch let's you choose between heating or cooling.  It really feels like it heats and cools, however it's just relative to your body temperature.  Using an infrared thermometer I found that the metal plate the can sits on heats or cools about 7 degrees F higher or cooler than the surrounding temperature.  It lists PC requirements (really?) and with such poor documentation and basic construction I wouldn't trust to leave it powered on unattended.  I would be afraid it would blow out a USB port or USB power supply.