This is a used MS-20 MIDI CONTROLLER from the Legacy Collection. See manual here: https://cdn.korg.com/us/support/download/files/feef2bca9a4f84c86ca0224cee8d7c6f.pdf
Please note, this device does not make sound itself, but can be plugged into either desktop or mobile software to model to KORG ms-20 semi-modular synthesizer.
A little dusty but I’ve cleaned it up. Missing one knob. Can include patch cables if you are interested.