These high-strength ARP bolts are great for installing most accessories. The 180,000 psi tensile strength bolts are made of 8740 chrome moly with a black oxide finish. All bolts are packaged in sets of 5 bolts with matching washers. These bolts have a 1/4-28 UNF thread pitch and 1 1/2" under-head length (total shank length including threads). 5/16" 12-point head.