The product's brand as the YZ, models for JB4446 and JB4447, nominal length is 8 ~ 20 mm, the thread tolerance is 6 g, black surface treatment for oxidation, material is carbon steel 22 h, product specifications for the m8 - m80, thread specifications for m8 - m80, Allen process for cold heading.Metric system is complete, high quality products, affordable, door-to-door throughout the country.