This pickup is designed to give a truly authentic acoustic guitar sound. Unlike most other magnetic pickups which give an electric guitar sound, the SH 145 Prestige gives a crisp natural acoustic sound. It is built as a stacked humbucker using powerful samarium cobalt magnets. Adjustable pole pieces are trimmed to provide a perfect string balance for the acoustic guitar strings. As it is a humbucker, it is free of 50/60Hz hum. A complete shielded case and low impedance output protect it from outside magnetic disturbances and makes it totally hum-free. Electronic circuitry is powered by a single 3V cell battery with an extremely low power consumption. Volume control and easy installation make this award-winning pickup one of the user-friendliest pickups on the market. An endpin connection cable for permanent installation and a detachable quick mount 12ft (4m) cable are included. This pickup has received in the shortest time the most favorable test review in music magazines worldwide. The pickup fits to sound holes from approx. 87mm [3.43in] up to 105mm [4.13in]