The grade G steel hex flange nut has self-locking distorted threads and a black phosphate and oil finish, and meets Industrial Fasteners Institute IFI 100/107 specifications. The nut has a flanged base on one end that eliminates the need for a washer when fastening components and a hex body that tightens from the side with a wrench, enabling use when there is limited space above the nut. 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. Grade G steel is often used in applications where strength is the primary consideration. The black phosphate and oil coating offers corrosion resistance and 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.