Hex Head Cap Screw Head Type Hex Diameter 5/16 In. Grade 8 Material Alloy Steel Finish Plain Thread Size 5/16-18 Thread Type Coarse Length under Head 2-1/2 In. Thread Length 7/8 In. Head Height 13/64 In. Head Width 1/2 In. Thread Style Partially Threaded Thread Direction Right Hand Tensile Strength 150 000 psi Rockwell Hardness C33 to C39 Meets/Exceeds SAE J429 ASME B18.2.1 Refills 2EA85 Package Quantity 50