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 Coarse Thread, manufactured with a medium presence in terms of the percentage of carbon, tempered with a high resistance to work in automotive and metalworking industry, it is manufactured with a load test of 150,000 PSI, we identify it by six marks or lines that it has in the upper part of the hexagon.