Hex Head Cap Screw, System of Measurement Inch, Basic Material Steel, Material Grade Grade 8, Fastener Finish Plain, Dia./Thread Size 5/16 In.-18, Fastener Length 2 1/4 in, Fastener Thread Direction Right Hand, Fastener Thread Type UNC (Coarse), Fastener Thread Style Partially Threaded, Fastener Industry Standards ASME B18.2.1, Head Type Hex, Min. Thread Length 7/8 in, Head Height 13/64 in, Head Width 1/2 in, Package Quantity 400