Rare Earth™ polepiece magnet responds to banjo head vibrations via a thin steel "inductor" placed beneath the banjo bridge. This is a proven design for a natural sound. The pickup and battery clip mount on the banjo's rim rods, with a 1/4" jack affixed to an easily mounted resonator flange bracket. 9-volt battery required. For Mastertone-style banjos. Includes a built-in preamp.