The product's brand as the YZ, models for Q619, head for the cylinder head, trough type for Allen, nominal length is 8 ~ 20 mm, the thread tolerance is 6 g, surface treatment is galvanized, material is carbon steel 45 h, product specifications for the m10 - m60, thread specifications for m10 - m60, Allen process for cold heading.Metric system is complete, high quality products, affordable, door-to-door throughout the country.