The Metal Master is the world�s most advanced heavy metal distortion pedal. DigiTech�s exclusive AudioDNA� technology is what makes the Metal Master more than your standard distortion stompbox. Rather than working from a single distortion type circuit with tone controls, the Metal Master features a Morph knob which blends between three totally different metal distortion types. This gives you a wide variety of different metal distortion sounds that can be dialed in quickly and easily. 1. Level Knob Controls the effect�s output level. Turn this knob clockwise to increase the output level, and counter-clockwise to decrease output level. 2. Low Knob Controls the boost or cut of low frequencies. Turn this knob clockwise to increase the low frequency content, and counter-clockwise to decrease the low frequency content. 3. AC Adapter Jack Connect a DigiTech PS200R power supply to this jack. Use the proper supply for your area�s Mains line voltage