Sir Compre is a compressor and a drive pedal in one. Basically, it's a "1knob compressor" that's really easy to work with. Turn up the Comp knob and it compresses... easily! But it also has a Tight knob that cuts into the bass so as not to get too boomy, The three knobs at the top work as a drive pedal with Volume Tone and Drive. Hint. be careful how much you turn up the Comp, Volume and Gain knobs. If you turn all three up too much, the noise level will be high, the