Application: This hammer head nut is mainly used for European standard aluminum extrusions nut model EU20-M5 High Hardness: Made of high quality carbon steel, these nuts have high hardness and long service life Durability: The surface is coated with Nickel for good rust resistance and better corrosion resistance Convenient to use: They are easy to use and convenient to connect aluminum profiles with other parts Package included : There are 100 pieces EU20-M5 nut in total