via
this auction
"If you don't know what this thing is, it's a crazy synthesizer controlled by the microphone. You can sing into it and it accompanies you with a corresponding synth sound. That is, if you sing a 'C' it will make a 'C' sound with the selected instrument. It does some recording... It also has rhythms and other functionalities."
Update via retrosynth in the comments: "It's an ESQ-1 digital synth engine without the analog filters. Interesting, and supposedly useful for thereminists for doing pitch to MIDI conversion. I personally thought it sucked for pitch to MIDI but I never tried it with an electronic source such as a synth or theremin, just guitar and piano."
Update via larriji in the comments:
"I have one of these. Two of my friends started the Breakaway company and when they dissolved it I inherited one. I wish I had gotten more of them. I have use this extensively back in the days when I was doing dance tracks with Psychic TV. It works great with synths as the sound source. The kazoo aspect I found very limited. The cheese element outshines your musical intent when humming into it. But it actually is a very helpful tool when using it with synths. Since it forces notes to pitch you can come up with some very interesting and usable "accidents". I used this on some tracks on PTV's Trip Reset. Does anyone know what these sell for? I have friends who want one. I have no idea the current value. A note of trivia here. Roman Babiak, cofounder of Breakaway said Stevie Wonder was one of their first customers. He picked one up at a NAMM then after trying it called them up and bought another one. I thought that was kinda trippy. I would be curious what he used them on."