The MXR Dyna Comp is a compressor pedal designed for guitar players. It's a signal limiting processor, which varies its gain so the output signal that you set remains constant. This compression circuit is coupled with a sensitivity control. This combination of controls made the Dyna Comp one of the most popular guitar compressors ever. For overdrive or clean sounds, you get increased sustain and superb tone. MXR M102 Dyna Comp Compressor Pedal Features Output & sensitivity foot control knobs LED on/off indicator Powered by the Dunlop ECB-02 AC Adapter and/or 9 volt battery The MXR Dyna Comp is a compressor that allows you to set an output level and the sensitivity at which it kicks in. This device can produce that percussive, clicky sound on a clean guitar - the mainstay of 80s pop players - or a mellow sustain for lead work. The M-102 is designed to capture the sound and performance of the originals which it does with an authentic vintage flavor. Rack spotters may have noticed several Dyna Comps in Dave Gilmour's monster system.