The P91 is an H4 pickup in a P-90 style housing, using two bar-loaded coils for that "Balls to the Walls" tone. This pickup is often considered the "81" of the passive group because of its exceptional qualities in a high output pickup. All HZ Pickups have EMG's exclusive 5-wire quik-connect output allowing any number of wiring combinations, and are fully shielded for a minimum of noise. String grounding is recommended to further decrease noise.