Seymour Duncan's best selling pickup model is the SH-4 "JB Model" humbucker, that originated from a pickup Duncan made in the early '70s for his hero Jeff Beck who had the PAF pickups switched out of his guitar by a dishonest guitar tech. Beck used the pickups in his seminal release "Blow By Blow" in a guitar built for him by Seymour, dubbed the Tele-Gib, which featured a JB pickup in the bridge position and a "JM" or Jazz Model pickup in the neck. The JB was never an official signature pickup, and Duncan cannot use the name Jeff Beck.
PAF ("Patent Applied For"), is an early model of the humbucker guitar pickup invented by Seth Lover in 1955. Gibson began use of the PAF on higher-model guitars in late 1956 and stopped in late 1962.