It's a wireless keypad (the part with numbers) and mouse combo. There is a wireless USB receiver in the mouse battery compartment. These both take AAA batteries (I believe). It's really to help with laptop keyboards (or tenkey-less keyboards).
It works fine.
You can come here, or we can meet nearby. You can try it and make sure it works. Sale is as-is/where-is. I accept cash, venmo, cashapp, and some others. Thanks for looking!