This amazing system consists of a high-quality hum-cancelling Stack pickup and an on-board omni-directional electret condenser microphone. It features master volume and mic blend controls. The Seymour Duncan SA-6 Mag Mic Acoustic System consists of a high-end active magnetic soundhole pickup with internal microphone and on-board buffering and blending. This impressive system has been used by such players as Ben Harper David Lindley Lenny Kravitz Keb Mo Jeff Pevar (CSN) Kelly Joe Phelps Peter Stroud (Sheryl Crow) Xavier Rudd and Bill Frisell. Hum-Cancelling Quality The SA-6 Pickup is a professional-level hum canceling Stack® pickup with an on-board omni-directional electret condenser microphone. The entire tonal spectrum of the acoustic guitar is accurately amplified. Controllable Settings You can get customisable with the master volume control and mic blend control. The magnetic pickup is always on. Blend in to add sparkle and detail to the overall tone or blend out for more feedback resistance from the pickup. It has twelve adjustable pole pieces which allow the best possible string balance regardless of neck radius. For High-Quality Acoustic Guitars (3.25″ to 4.20″ Sound Holes) This pickup is designed for high-quality 6- and 12-string acoustic guitars with sound holes between 3.25″ and 4.20.”