Rickenbacker’s first electric bass, the 4000 was a single-pickup model with a comparatively unadorned appearance. It was introduced in 1957, and was joined just four years later by the twin-pickup 4001, which boasted neck and body bindings, as well as triangular fingerboard markers (the 4000 had only dot inlays).

From around 1963, the 4001 also featured the latest version of the company’s distinctive string mute, whose dampers, located in the instrument’s bridge/tailpiece assembly, could be raised and lowered by means of two thumbscrews.

The 4001, like Rickenbacker’s 6-string guitars, benefitted considerably from it’s association with The Beatles.