This is a Pair of Original GM Rear Differential Side Gear Thrust Washers GM# 531776 Later Replaced by GM# 3846425. These are Correct for the 1959-1976 GM Full-Size Chevrolet, Pontiac, Buick and Oldsmobile Cars as well as A- Body Chevelle, Lemans, GTO, Cutlass 442, Skylark and Grand Sport With the 12 Bolt Rears. Incorrect for 10 Bolt Differentials. Diameter is 3" OD, 1 3/4" ID. These are from a Former Pontiac Dealership Parts Stock and are in Good Condition. The GM Package is Not included. FREE SHIPPING IN THE US.