This is the stock preamp that comes with carvin basses. 501B. It's an active 3 band eq with volume and blend knobs. The volume knob is also a pull switch to make the bass passive. The battery clip is still attached. Also included is a switch that was used to make the humbucker a single or doube coil. The pickup is the HB5W humbucking pickup for 5 string basses with wide spacing. This looks like a stingray pickup but will NOT fit a normal stingray 5 cavity. For more info check out this page. I'm not going to lie about this stuff. The reason i replaced it was that i didn't like the way it sounded. Everything looks and works fine though. The preamp retails for $80 and the pickup for $90. I'd take $90 for both plus shipping. If you want just one, make me an offer. Thanks for looking Brian.