Hex Nuts are used for fastening to a hex head cap screw or bolt when mechanically joining materials together. Made from alloy steel. Use stainless steel where corrorsion is and rust is of concern or in exterior applications. Best for general hardware use or where high strength is not required Diameter: 5/16 inch Thread Pitch: 18 Thread Type: UNC Head Type: Hex Material: 18.8 Stainless Steel