The steel key stock has a gold dichromate finish, meets Deutsches Institut für Normung DIN 6880 and British Standards BS 4235 specifications, and has a standard tolerance. The steel material provides a good balance of toughness, strength, and machinability. It is magnetic. The gold dichromate finish provides corrosion resistance and a gold appearance.

Key stock is used to make a machinery part known as a machine key, which fits into a mating keyway to transmit torque between shafts and hubs or bushings. Rectangular and square key stock shapes are the most common, while step key stock is used for damaged or inconsistent keyways.