It is a metal piece, whose function is to join two or more elements, this type of bolt has a hexagonal head, made of carbon steel, quenched and tempered, high resistance for use in the mechanical and automotive industry, its load resistance is similar to that of the grade 5 screw, it is identified by the number that it has in the upper part of the hexagon. The finish of the screws is black with different thread pitches, keeping in mind that by mentioning a 960 screw we mean that it is a partial thread.