When an octave bass accompaniment just isn't enough, the Boss OC-3 Super Octave steps in to sweeten the deal. In addition to the original OC-2 mode allowing for one and two lower octave notes, the OC-3 includes a Drive and Polyphonic mode for overdriven tones and an adjustable polyphonic effect. The OC-3 is used by The Black Keys, Van Halen and Tony Iommi.