This appears to be the standard computer security lock that fits in the case of most classic Macs, and maybe drives, monitors and printers.
If your device has an opening with an icon of a chain or lock that is approx 3/4" x 3/16" then this will work. Total length is approx 1-3/4".
Insert the lock from the inside of the computer and run a cable through the hole to secure it from theft.
This one is marked "Grimes" USK-08 on one side and 2 on the other.