Do you feel the need to express yourself fully? The M-Audio EX-P Expression Controller Pedal works with all M-Audio MIDI controllers that have an expression pedal input. A built-in polarity switch ensures compatibility with most other brands of controllers and keyboards. Use the EX-P to control any assignable variable MIDI controller value, including volume, modulation, pan, filter sweep and much more. Durable molded construction with integrated cable.