ARP stainless steel bolts are rated at 170,000 psi to provide a substantial extra margin of safety over Grade 8 and other hardware. They're available in hex head or 12-point styles and a variety of lengths and sizes for use on cars, boats, trailers, and more. Stock up on these truly maintenance-free bolts so you'll have them when the need arises. Order the ARP stainless steel bolts designed to fit your application. Bolts, 12-Point Head, Stainless 300, Polished, 5/16 in.-24 RH Thread, 0.750 in. UHL, Set of 5 Features: Fastener Size: 5/16-24 in. RH Underhead Length (in): 0.750 in. Fastener Head Style: 12-point Fastener Material: Stainless steelFastener Finish: Polished Fastener Grade: ARP Stainless 300.