MXR Poly Blue Octave

The MXR Poly Blue Octave brings modern and classic pitchshifting
styles together with fuzz and modulation to create the ultimate
octave pedal for tonecrafters and sonic seekers.The Poly Blue Octave
features four separate octave divisions—one octave down, two
octaves down, one octave up, and two octaves up—and you get to
control the level of each in the mix. Each is polyphonic by default,
which means they sound just as amazing with chords as they do
with single note passages.