- Japanese Korg Monotron
- Midi if assembled in Japan by MIdi-if for Korg Monotron Inventor Motohiko Takeda
- Handmade cable extension for midi-if box (USA)
- Radio Shack’s Midi-if case and knob
You can find it on eBay, but it isn’t cheap.
Thanks for @discchord for pointing me at this video.