These serrated hex nuts with flanged collars are available especially for carburetor, valve cover, front cover, oil pan studs and windage tray studs. Made from premium-quality material, they are cad-plated. All general purpose nuts are rated 150,000 psi tensile strength. PartNumber : arp400-8610 Description : Serrated Flange Nut; Single Piece Socket : 1/2 Size : 5/16-24 Material : Stainless Steel Engine Components::Hardware Kits - Other