This effect pedal is a 7-band graphic equalizer. Each slider cuts or boosts a one octave wide band. Each band is like a tone control which only affects a narrow part of the sound spectrum. The FX40B has seven equalizing sliders and one level control slider. When the sliders are moved to change the sound, the pattern made by the slider knobs graphically shows the equalization curve created by the pedal. The graphic equalizer allows you to change the sound or tone of your instrument and effects, lets you get more gain from your P.A. system before feedback, and lets you compensate for inadequacies in your P.A. The level slider lets you adjust the output of the graphic equalizer to make up for the equalization you apply.