Space Mouse Pro Wireless - Long wire with USB connector and a smaller connector

[Chip]

Hi, I'm hooking up my new Space Mouse Pro CAD mouse. One of the cords that came with it has a connector on the end of the wire that does not fit into the mouse. This cord has a USB connector on the other end. Any idea what this wire fits? There is a smaller wire that does fit the mouse and computer, for charging the mouse.

[lipdive]

Usually, the smaller cable you mentioned, which fits both the mouse and your computer, is for charging the mouse's battery.
To confirm the purpose of the cable with the USB connector, you might want to consult the user manual or documentation provided by the manufacturer. If you can't find the information there, reaching out to the manufacturer's customer support could also help clarify the cable's purpose.