via this auction
"If you're looking at this you probably already know what this is. If not, this is a very cool, vintage guitar synthesizer effect designed for guitar (but works with other instruments, too). Basically, you can use your guitar to trigger these analog drum sounds and/or bass down octave, with or without fuzz. You can blend in the guitar with its 3 "Color Tones" or have it just play the synthesized sounds. Very cool, vintage box in really great condition.
Comes with original, fully operational case. Original foot switch is in perfect condition and is included."