ARP nuts are made from aerospace-quality material with 12-point style heads. Available in chromoly or stainless steel, they come in many sizes to meet just about all of your needs and are rated at 180,000 psi tensile strength.Nuts, 12-Point, 8740 Chromoly, Black Oxide, 7/16 in.-20 RH Thread, Set of 10Features:Thread Size: 7/16-20 in. RHNut Style: 12-pointNylon Insert: NoSelf-Locking: NoWrench Diameter: 1/2 in. Nut Material: Steel Nut Finish: Black oxide Washers Included: No Fastener Yield Strength (psi): 150,000 psi Quantity: Sold as a set of 10