The M288 Bass Octave Deluxe is a dual voice octave pedal that offers analog tone, true bypass, and a variety of tonal options. Use the Dry knob to mix in your direct signal, and hit the Mid+ switch to add up to +14dB of internally adjustable mid frequencies (400Hz or 850Hz). Finally, mix in two separately controlled octave voices-Growl for throaty tone and Girth for deep tone. Constant Headroom Technology provides high headroom and superior tracking. Power: Dunlop ECB-03E AC adapter or single 9 volt battery.