The Big D is an extremely versatile distortion pedal capable of many different sounding ranging from a light bluesy ovedrive to modified hi-gain tube amp distortion. The Gain control varies the amount of overdrive. The Level varies the output. it sounds best if set a bit louder then with the pedal turned off and the Tone control the amount of bass response for a really BIG growling tone! 5-way Diode Select: Left to right, 1. Classic overdrive, tight and controlled 2. More output and gain then #1 3. Still more output and gain, increase bass response 4. More output then #3, less clipping, a more open sound 5. Less overall output verging on fuzz with slight compression. It also ahs a clip that changes the dynamics of the clipping. Hard: Increases output, less clipping Soft: Less output, more clipping.A lot of control over the type of overdrive - this pedal can do all your distortion pedal jobs from blues to hard rock, to metal on up to vintage fuzz, and modern industrial type tones.Very high quality, very well made and impressive - we sell a lot in our shop just trying them out. RRP $549