Spline Count: 30 Material Type: Steel Finish: Black Oxide Color: Black Sold in Quantity: Each Notes: Does not fit Olds 12 bolt. Will not work in posi carriers. Info Works on 1965-76 Chevy passenger car 12-bolt rearends with 8.875" ring gear and 30-spline axles. Economical way for all race cars to "lock" the rearend. This locker will not work in posi rearends.