Hex Head Lag Screws, Material Steel, Finish Zinc Plated, Screw Size 5/16 In., Fastener Length 4 1/2 in, Threads per Inch 9, Thread Style Partially Threaded, Minimum Thread Length 3 29/64 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 50