The MB-2B Midboost/Fat Control boosts a wide mid-frequency range for a more distinct natural frequency boost than any other midboosts. The frequencies selected give your guitar the best response and sustain possible. The MB-2B Midboost/Fat Control used with a stratocaster (single coil) type pickup produces a sound very similar to the old Gibson P90 pickup. Used with humbucking type pickups, the sound is transformed into that of super humbucking pickups. The MB-2B Midboost/Fat Control produces the sound equivalent of adding 5,000 feet of wire to your pickup, and at a turn of the knob the MB-2B Midboost/Fat Control will respond by adding any amount of midboost you desire. There is one control on the unit: Flat/Fat, plus a foot switch to bypass the effect, and an LED to indicate effect operation. Flat/fat affects the midboost/buffer which includes a wide variable gain mid-frequency power booster control and a built-in low impedance buffer. Inputs/outputs: there is a 1/4" input jack on the right-hand side of the pedal, and a 1/4" output jack on the left-hand side, with a battery switch on the input jack. Power supply: 9 volts DC, internal or external. Internal using a 9 volt battery (for battery access, remove the four screws on the sides of the unit and pull apart). WARNING: If battery drops below 7 volts, noise will occur. External using a 9 volt regulated power supply, mini-plug, tip positive.