It is a piece with a central hole, which has a thread, which is used to attach to a screw in a fixed or sliding way. The nut allows fastening and fixing joints of removable elements, made of low carbon steel and have a load resistance of 90,000 psi, these are identified because they do not have any mark on the nut. It is a nut with a metallic zinc finish. It has a semi-gloss appearance and is often used to protect steel from corrosion.