This kit is a Grade 8 Stainless Steel ARP (American Racing Products) crank pulley bolt & washer kit to bolt the crank pulley to the harmonic balancer on the Cadillac engines. These are not only good looking, and don’t rust, but they are super strong and have a polished finish. They have a tensile strength of 170,000 psi. They have a 6 point head and a .625 diameter flange for easier access in the tight spots. This kit also includes AN stainless washers.