This overdrive pedal allows you to switch between two modes: FLAT, which accentuates the tone of your guitar and amp, and MID, which creates a solid distortion. The TONE control, set to a one-octave higher range than typical overdrives, produces a beautiful overdrive sound with a flat response while preserving harmonics. Used only a few times. I think it's in excellent condition. Operation confirmed. Comes with the box.