By cons, it is small (smaller at the keys would be too much for me), and light (if ever you use it with a laptop computer which is not my case).
I think the key 000 is useful (mind you, on some keypads there are only 00 and not 000), as the deleted key. (By cons, it is placed between the plus and minus button. Questionable design choices) ..
When I plug my keyboard to the USB port, it does not. (I have not yet taken the time to use a USB key).
