ARP are the leading brand in fastener technology. All fasteners are made with the highest quality materials with quality assurance testing. ---- As the crankshaft flexes and twists, the harmonic damper absorbs incredible amounts of kinetic energy. To ensure that the damper is locked in position, ARP has developed these ultra-strong 190,000 psi bolts that let you exert maximum clamping force. Special features include1/4˝ thick, wide area washer and an extra tall 12-point head that accepts a deep socket and eliminates the worry of striping the head.