Electro-Harmonix LITTLE BIG MUFF PI Distortion/Sustain PedalThe Little Big Muff Pi from Electro Harmonix is a harmonic distortion sustain pedal for the electric guitar player. The Little Big Muff Pi is identical to the Big Muff Pi, but in a compact, smaller die cast chassis. This pedal features Sustain, Tone, and Volume controls. The Footswitch toggles between effect and bypass modes. A 9V battery is included with the unit and an optional 9. 6 VDC 200BI power supply is available. True bypass Singing sustain