An effects unit that achieves a variety of octave effects. - Model: OC-3 - Type: Octave Effect - Input/Output Terminals: Guitar Input, Output (Mono), Direct Out, Bass In - Controls: DIRECT, OUTPUT, RANGE, CHECK - Brand: BOSS Thank you for viewing. The rightmost knob is broken. The effect sound has been confirmed, and the operation of the other knobs has been confirmed, so please consider this if you are okay with a fixed setting or can repair it.