https://www.rickysounds.co.uk/product/4001-hairpin-truss-rods/
"Hairpin" Truss Rods for Rickenbacker 4001 - Made By RickySounds - For Everything Rickenbacker
Oct 8, 2026 - Replacement for all 4000 series basses made between 1965 and 1982. Complete with Nuts washers and thrust plate. We have re-engineered the old style "Hairpin"...
truss rodshairpinrickenbackermadeeverything