This mouse is not a nano sized mouse. The bluetooth receiver however is. It works as you would expect, the receiver is tiny so little to no risk of catching it or knocking it.
The mouse itself is very neat, the back opens up to reveal the battery holder and in the centre there is a slot for the bluetooth receiver to be placed in to when not in use.
One of the features is the ability to turn it off when not in use to preserve the batteries (hold down the small button on the bottom for 5 seconds.
Overall a great mouse, very happy.