Fender introduced the Mustang Bass in Fullerton, California, as a companion to the Mustang guitar line. It carried a 30-inch scale, two single-coil pickups, and a unique four-saddle bridge that stayed in production until 1982.
Early 1966-1969 examples used a slab body and separate volume and tone controls per pickup. By 1970 the wiring shifted to a master volume and tone setup, and CBS-era models added a three-bolt neck plate before production ended.
Short-scale fans in punk and indie scenes gravitated to the bass for its easy playability. Krist Novoselic relied on a 1969 model for the raw tone on Bleach, while later players modified them with hotter pickups or PJ configurations.