Vintage '70s 1970s Mu-Tron Mutron Musitronics Octave Divider. The legend!
Here is one of the Mt. Rushmore pedals, the legendary Mu-Tron Mutron Musitronics Octave Divider. This is a vintage edition in great working condition. The only modification is the addition of a three-prong cord that is shorter than the original, which is actually quite convenient for using on a pedal board and has zero impact on performance. It sounds as good as you imagine. Rubbery, thick octave tones mixed to your liking with your original guitar signal. (I ended up with two vintage versions and a reissue, so I am selling one of the vintage units to keep the reissue, which takes up less space on the pedal board.)