Not mentioned anywhere on the box and no included instructions. There is a switch marked I and II.

I initially thought it was for two speeds of cooling (normal and fan-forced), but it's actually toggling between hot and cold. I is hot and II is cold.

Now I have to wait for my hot can to cool down.

I buy this and then question why, The fridge is cool but it isnt as cool as it makes it out to be. It only cools a little tiny bit of the fridge so if you want a “novelty” just because its a tiny fridge then get it other wise stick to the real one (P.S Don't do my mistake and leave it on “heat” for 2 long other wise it burns out and melting plastic smells takes over the whole room)

Upon discovering such an item exists, I did what most normal people would do an bought this immediately!! Who in their right mind would not want a miniature fridge on their desk at work– Anyway, long story short, the idea of this is far better than the actual capability of it as a functioning fridge. I experimented with it for a week, changing settings and letting it ‘cool’ for extended periods of time, it never made my Coke anything cooler than it would be if it was left outside on a cold day. If you can ignore the fact that this does not work like it should, then get it. As far as novelty goes, its brilliant but in terms of practicality, its poor. Thankfully MA were good enough to offer me a full credit… I still have hope for a USB fridge that works one day, sadly that day is just not today.