The nylon 6/6 hex nut has a black color. It has six flat sides that a wrench can grip to turn from the side, enabling use when there is no space above the nut. Nylon 6/6 provides resistance to abrasion, corrosion, and many chemicals and solvents. The material is a strong yet lightweight plastic and is nonconductive. Nylon 6/6 can either absorb or lose moisture, which may alter its dimensions and mechanical properties.

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.