This is an original 1965-1966-1967-1968-1969-1970 Chevrolet Axle for all 10 bolt Impala, Caprice, and Bel Air models. The left and right axle are interchangeable and has the unique tip that uses a locking ring to secure the axle to the differential. It is a 28-spline end. The key difference between 1965 and 1966-1970 is the shaft size for where the axle is seated. See chart for specifics.
* Note location for determining axle length is different than GM specs