It is a metallic piece, whose function is to join two or more elements, this type of bolt has a hexagonal head, it is a Fine Thread, made of low carbon steel, quenched and tempered, which makes it a bolt with a lot of load resistance (120,000 PSI), being highly resistant to loads, it is used in the automotive and metalworking industry. The identification of this bolt is by three marks or lines leading to the top of the hexagon.