Back by popular demand, the MXR flanger creates a variety of wild sounds from dynamic jet plane or cool space effects to short delay, chorus and vibrato. Back off Width to zero to disengage auto-sweep, then use the Manual knob to physically place the effect anywhere along the frequency spectrum; Use with guitar, bass, keyboards or vocals! Power: Two 9-volt batteries (some early models may not have this feature), or Dunlop ECB-004 18-volt AC Adapter - Controls: Footswitch toggles effect on/bypass (red LED indicates on) Manual knob selects frequency center of effect when auto-sweep is disengaged Width knob at zero disengages auto-sweep, rotates clockwise to increase total phase sweep of effect Speed knob modulates rate of effect Regen knob feeds effect back onto itself at adjustable intensity, increasing the total phase effect.