This is Keeley Electronics C4 Compressor for guitar.. the C4 model has the extra knobs for ultimate control and shape of your compression signal. I find this pedal to work amazingly with Fender or Fender-styled instruments Strats/Tele's with single coil pickups, and clean amps, so if you into country/jazz/light OD man this always does the trick gluing things together and honestly, make soloing easier. It has that dyna-comp feel to it.
Also, this works as a great bass guitar compressor when you go direct into a DAW (limits that bottom end without killing it) and also works with microphones. So, don't limit the scope of it's utility in the studio. I have to part with some things for financial reasons. It's in excellent working condition and has a few cosmetic flaws