M-Audio EX-P Expression PedalEX-P - Universal Expression Controller Pedal! Feel the need to express yourself fully? M-Audio"s EX-P expression controller pedal works with all M-Audio MIDI controllers thathave an expression pedal input. A built-in polarity switch insures compatibility with most other brands of controllers and keyboards. Use the EX-P tocontrol any assignable variable MIDI controller value including volume, modulation, panning, filtersweep and more. Durable molded construction with integral cable.