The SD-1 Super OverDrive pedal produces the warm, natural distortion of an overdriven tube amplifier while maintaining the subtle nuances of a player's picking technique. This is one of BOSS' more subtle and smooth overdrive pedals, perfect for blues and rock. * Compact overdrive pedal with warm, smooth overdriven sounds * Unique asymmetric overdrive circuitry for a classic, natural tube amp growl * Tone control provides precise adjustment of drive sound