Timing pinion.
CELORON VITEX 5116 Bis.
For GMC Chevrolet years 30/40
54 teeth.
Outer Diameter = 154.7mm
Center diameter = 2.5mm
Thickness = 23.6mm
Old store stock but stored without packaging.
There are therefore traces of storage on the central metal part (visible in photos 5 and 6).