For use with an externally threaded item that measures 5/16 inch and has 18 threads per inchPackage contains 50 piecesHeight: .266"Hex Socket Drive 1/2"304 stainless steel offers good corrosion resistance in many environmentsHex nuts are used with mating screws and bolts to help secure items. They have a hex-shaped body, which has flats that can be gripped with a wrench for turning to tighten and untighten in fastening applications. Allowing for easy assembly and disassembly, hexagonal or hexagon nuts are the most common nut type.