ARP's premium grade header stud kit is an excellent choice to facilitate the installation of your vehicle's exhaust headers. To maintain a reputation for "zero defects", ensure optimum quality control, and produce fasteners of exceptionally high quality, ARP controls all aspects of the manufacturing process, performing all operations in-house where they can be closely monitored. ARP takes extraordinary steps to produce the very finest products of their kind on the market today. Manufactured from heat treated 8740 chrome moly steel with a black oxide finish, these studs are rated at 170,000 psi tensile strength, which is substantially stronger than Grade 8 hardware. The 3/8" diameter studs have a 1.670 overall length, and the 12 piece set comes complete with premium-quality washers and compact 12-point style nuts that are great for tight, hard-to-reach areas.