Three function knobs, Comp (The on/off LED changes from green to red depending on the amount of compression used), EQ (Counterclockwise adds warmth, clockwise adds more brightness, very musical control knob, center dent), Volume, and a small beefy high/low toggle switch that acts like a beam to focus the compression (the sounds range from the sweet spot like the BOSS CS-2 offers, or a deep focused compression for five and six string bassists), smooth & silent on/off switch, 18V power supply and instructions included