From Bartolini:
The MV5CBCB is the Music Man® style bass replacement pickup. It fits 5-string Music Man StingRay basses up to 1992 & “Classic Collection” basses. The dual coil design features powerful lows, low-mids, and a bright treble.
The “Classic Bass” series bass pickups are passive designs featuring an extended and more resonant frequency range. They have far more “air” and definition at the top without sacrificing lows and low mids. They are cast in epoxy to remove unwanted feedback and microphonics