Catalinbread Callisto Chorus/Vibrato Guitar Effects Pedal A twist of the DENSITY knob continuously adjusts the delay line time delivering classic chorus sounds from fat and warm to airy and subtle The sweep depth of the chorusing is controlled by the WIDTH control MIX knob smoothly dials everything from lush chorusing, to true pitch vibrato, to sea sickening warble, and has the ability to run clean dry to completely wet The RATE range can go from slow and syrupy to almost ring-mod intensity Can be powered with a standard 9V battery or a regulated 9V center-negative DC external power supply