Here's what EMG say about the 35 P4X pickup
The EMG 35P4X is our P bass pickup in an Extended range housing with the treble magnet closer to the neck (like a Spector or Yamaha bass). The EMG 35P4X covers a wide sonic palette of classic and modern bass sounds. Because the 35P4X utilizes ceramic magnets coupled with short, squat coils, the tone has brilliant high-end articulation, warmth, and incredible low end punch.
With the EMG X preamp on-board, you get even greater dynamic control and touch sensitivity, much like a passive pickup. For players who want a "Fender" P alignment - with the treble side closer to the bridge - we offer this pickup in "reverse". Utilizing EMG's solderless wiring, this pickup is easy to install at home. This pickup uses a 35 Extended housing that is 3.5 inches (89mm).