Martin Robert Turner is an English musician best known for his time as the bass guitarist, lead vocalist and a founding member of the rock band, Wishbone Ash.

The Rickenbacker 4001 is an electric bass that was manufactured by Rickenbacker as a two-pickup "deluxe" version of their first production bass, the single-pickup model 4000. This design, created by Roger Rossmeisl, was manufactured between 1961 and 1981, when it was replaced by an updated version dubbed the Rickenbacker 4003. Variant models of the 4001 include the 4001S, 4001LH, 1999, 4001V63 (reissue), 4001CS and the 4001C64 and 4001C64S: the C Series is a recreation of Paul McCartney's left-handed 4001S with a reversed headstock. There are also Al Cisneros and Lemmy Kilmister signature versions of the instrument.