This is a brand new set of 4 inner (small) and 4 outer (large) cylinder base hex nut. 3/8″ x 26 TPI.
Fits: Triumph pre-unit 500cc and 650cc up to 1962 and unit 650cc models up to 1968
Inner small nut part # W76, 37-0076
Outer large nut part # PO172A, 60-4261, 82-3955, 99-0047