ARP's Custom Age 625 Plus material is newly formulated super-alloy demonstrates superior fatigue cycle life, tensile strength and toughness - with complete resistance to atmospheric corrosion and oxidation. ARP is the first to develop manufacturing and testing processes for fasteners with Custom Age 625+. Best of all, it is less expensive and expected to soon replace MP-35 as the material of choice in the high strength, super-alloy field. Typical tensile strength is 280,000 psi. Includes: Custom Age 625+ studs Parallel Ground Washers 8740 Chrome Moly Steel 12 pt Nuts 1/2 oz. Arp Ultra-Torque Assembly Lube