Product review (3 stars): Pretty good
It is OK. Very cute! It does not get a warm drink cold, or at least very well. It will keep a cold drink cold. The "I" position on the switch is for cooling, and the "II" position is for heating. I found you can put a small cup of coffee in it, and it keeps it warm quite well. It does not get cold on the inside, there is no insulation (I put foil around the inside and now it gets somewhat cool inside). It works by using a "peltier unit" which is just underneath the metal plate. It gets cold, there's a heatsink (brick of metal with fins) on the bottom of it, and the fan draws away the heat with the heatsink, and vice versa for heating mode. This radiates the temperature through the aluminum can or paper cup (works better with metal/cans). In cooling mode, after being on for an hour, gets to about 43 degrees F. Heating mode, 150 degrees F. You do not need a computer to use it, either. I use it on our wall outlet that has USB built in, and you can also use it with a battery pack or wall charger. Even in the car! Here's why I only give it 3 stars: because if I did not know how to solder, or fix electronics, it would be in the trash. The cord ripped out because it is barely held on to the inside. I also had to fix the door and add foil to insulate. Is it worth $20? Sure. But don't buy it for $40 from other sellers, because it would for sure be a ripoff.