Boss OC-20G

The BOSS OC-20G Poly Octave produces octaves for various combinations of strings (like the 5th and 6th strings) while leaving the other four strings unprocessed making it the ultimate octave pedal for use with GK-ready guitars. World's first polyphonic octave pedal for use with GK-equipped guitars Octaves can be assigned to different strings for simulated guitar/bass combos Onboard electric and acoustic guitar simulations plus Distortion effect Accommodates playing chords while using octaves Rugged dual-pedal design with simple knob-based controls *Note that optional GK-2AH pickup or equivalent required for use. Assignable Octave Processing Thanks to the GK Pickup input the OC-20G Poly Octave can produce octaves for various combinations of strings (like the 5th and 6th strings) while leaving the other four strings unprocessed for cool simulated guitar/bass combos