This is an exceedingly rare piece of history, one of the first inventions of the late John Blacet.
It's incredibly difficult to find much info on this museum worthy piece,
It comes with the original instruction manual which is also a build guide and full schematics.
Powering it up with two 9v batteries, it's kinda theramin like in sound.
The more pressure you apply to the piezo sensor is the amplitude of the sound, and the whammy bar looking thing is pitch.
It's quirky for sure, I can't tell if is 100% working, but it seems to respond to all the controls.
The wood enclosure could do with a bit of love.