This part is used to secure the fan and the component parts of the fanshaft. All waterloo built manual and power steering equipped tractors used this concept. Our part is the last style adopted by Deere. and replaces B2122R. It is an alloy steel part with a nickel finish. They usually are worn where they contact the die cast fan drive disc or are pitted by years in the field. They are still available from Deere, you can check the price.