Hex Head Lag Screw Material 18-8 Stainless Steel Finish Plain Screw Size 5/16 in Fastener Length 4 in Threads per Inch 9 Thread Style Partially Threaded Minimum Thread Length 2 1/2 in Dimensional Standards ASME B18.2.1 Pack Size Small System of Measurement Inch Drive External Hex Drive Size 1/2 in Head Height 0.219 in Head Style Hex Head Width 0.324 in Package Quantity 10