These pickups capture more harmonic content than traditional “M” style pickups due to their dual ceramic bar design. The uniform magnetic field of a bar magnet allows each note to have an accurate dynamic response and no information is lost as the string moves back and forth. These pickups sound great passive or can be paired with an onboard preamp, such as Aguilar's OBP-1, 2 or 3, for the ultimate in tonal flexibility. The AG 4M Pickup is direct replacements for 4-string Music Man style basses.