In short, this is a fridge
that sits on your desktop
The external size of the fridge tends to be about 1 foot deep by just less than 1 foot high. Its internal size is much smaller due to its insulation: they hold about 6 330ml cans. The whole unit is kept closed by a handle locking system rather than Magnetically.
Some models are able to run off mains supply as well as the ability to be powered from battery and through a car's cigarette lighter
The upshot of it all is that you can keep your milk cold for your coffee, this makes it a must have for self respecting geeks world-wide.