This unit works perfectly. No power supply is included.
"The Octapad first model, introduced in 1985, was the Pad-8. It was a very important device at that time, allowing drummers and percussionists the opportunity to trigger virtually any MIDI sound source without the need of a full electronic drum set. It had no internal sound source, and all pads were assignable to one note each. All pads were on the same MIDI channel."