Good condition, 6,5/10, Made in Japan, more info:

This vintage monophonic analog octave pedal generates a synthesized sub-octave tone precisely one octave below the original input pitch. Engineered during the early 1980s as part of the specialized PSE modular system series, it features a distinct wedge-shaped enclosure intended to dock into proprietary system pedalboards.

Control configurations include knobs for direct clean signal blend and octave volume adjustments. A defining technical feature is the unique phase-inversion polarity switch that alternates the input signal orientation. Internally, the circuit architecture utilizes dual JRC4558D operational amplifiers and shares its structural blueprint directly with the Korg OCT-1.