The BTC Control features a bass and treble equalizer on a concentric (stacked) pot. It takes up very little space and will work with any pickup, active or passive. It comes complete with knobs (including 2 extra volume knobs). BTC Controls and Systems are the most widely used bass EQ Systems in the world. Approximately 12db of cut and boost are available for bass and treble and all controls are center detented to assure quick return to normal tone settings. A dual-dip switch is mounted to the PC Board that lets you program the high end frequency response four different ways so you can choose the sound that´s right for you. These systems use the latest in surface mount technology, are extremely quiet, and require very little current from a 9 Volt battery.