Expresion PedalFeel the need to express yourself fully? M Audios EX P expression controller pedal works with all M Audio MIDI controllers that have an expression pedal input. A built in polarity switch insures compatibility with most other brands of controllers and keyboards. Use the EX P to control any assignable variable MIDI controller value including volume, modulation, panning, filter sweep and more. Durable molded construction with integral cable.