Octave OC-2 plus OC-3

Fusing classic BOSS octave tones with the latest tracking technologies, the BOSS OC-5 sets a new standard in octave pedal performance. Vintage mode provides a spot-on recreation of the legendary mono OC-2 from 1982, while Poly mode offers numerous enhancements for extended-range playing. And with the addition of an octave-up feature, a span of three octaves is now available for creative exploration. From fat, low mono sounds to octave-shifted chords and more, the OC-5 delivers the widest range, finest sound quality, and best playability in any octave stomp to date.

https://www.boss.info/us/products/oc-5/