The steel hex flange nut has self-locking distorted threads and a cadmium plating, and meets United States Military Standard Mil. Spec. MS21042 specifications. The nut has a flanged base on one end that eliminates the need for a washer when fastening components. Also called an all-metal and Stover nut, it has self-locking threads that are distorted to create friction against the mating threads, which provides resistance to vibration. The nut cannot be reused. The body has a hex shape with six flat sides that a wrench can grip to turn from the side, enabling use when there is no space above the nut. Steel is often used in applications where strength is the primary consideration. The cadmium plating offers corrosion resistance, especially in marine and alkaline environments, and provides lubricity. Width is measured as width across flats.

Nuts are internally threaded fasteners that are used with bolts and threaded rods and studs to connect components. Several different nut styles fit a variety of application and installation requirements. Some styles, such as hex nuts, acorn nuts, flange hex nuts, and coupling nuts, must be tightened with a tool. Others, such as eye nuts, thumb nuts, and wing nuts, can be tightened by hand. Some nuts have a self-locking mechanism, such as a nylon patch or distorted threads, that makes them suitable for applications with a high amount of vibration.