Volume pedal. Features: The Ernie Ball Most Valuable Pedal provides a super smooth foot sweep, ideal for precise volume control with no high-frequency loss at any volume. Works with both active and passive electronics, the MVP also includes a powerful gain boost allowing players to increase the audio signal up to +20 decibels. The MVP features a compact, rugged design consisting of aircraft grade aluminum housing that is virtually indestructible. Requires DC 9V/100mA minimum power supply or 9V battery.