Graph Tech Ghost Pickups, P/J Bass style, 4 String The PN-8304-00 is a set of ghost loaded pickups for a four string Jazz Bass or Precision Bass guitar.  They are a drop in replacement set to make for an easy install.They will work with any Ghost preamp kit.  Measure  Length Width  Height  E to E   inches 0.747"  0.335"  0.335" 2.250"  inches 3/4" 11/32" 11/32" 2 1/4" millimeters 18.97mm 8.51mm 8.51mm  56.80mm Ghost pickups contain a custom engineered piezo crystals that is encapsulated in a set of String Saver saddles. The ghost saddle pickups have a natural compression effect so you can play as hard as you want without overloading the input channel or experiencing the dreaded piezo "Quack". Pickups are individually calibrated so you get a precision-balanced set of ghost saddles, for even string to string output. Any set of ghost pickups can be used in conjunction with any ghost preamp kit as well as many others on the market.