The grade 2 steel machine screw hex nut has a self-locking nylon insert design and a zinc plating. Designed for use with machine screws, the nut has a flat top with a large bearing surface and chamfered corners. The nut has six flat sides that a wrench can grip to turn from the side, enabling use when there is no space above the nut. It has a self-locking nylon insert to help prevent loosening when the nut is threaded to another component. Grade 2 steel is often used in applications where toughness is the primary consideration. The zinc plating offers corrosion resistance and has a reflective appearance.

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 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.