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The grade 9 steel hex nut has a zinc yellow-chromate plating. 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. Grade 9 steel, composed of alloy steel, is stronger than grade 8 steel and is often used in applications where high strength is the primary consideration. The zinc yellow-chromate plating offers good corrosion resistance.

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.