As the crankshaft flexes and twists, the balancer absorbs incredible amounts of kinetic energy. To ensure that the balancer is locked in position, ARP has developed these ultra strong 200,000 psi bolts that let you exert maximum clamping force. Special features include 1/4 inch thick, wide area washer and an extra tall 12-point head that accepts a deep socket and eliminates the worry of stripping the head. Square Drive Balancer Bolts ARP offers a special version of its rugged 200,000 psi rated balancer bolt that can accept a standard 1/2 drive ratchet or breaker bar to facilitate rotating the crank assembly. 1/2 square drive forged into bolt head, enabling the rotation of an engine with any 1/2 drive tool Made from heat-treated 8740 chrome moly steel with heavyduty black oxide finish Harmonic Balancer Bolt Kit 12Point Head Diameter 1/2-20 Socket 1-1/16 UHL 1.55