Nechomah,
The older Bosch machines came with a metal “cap” that you click the wire whisk beaters onto. In the newer Bosch machines (4 -5yrs. old) that cap is PLASTIC. When mixing a cookie dough, if you use the plastic cap and whisk beaters, the whisks will bend or come apart and the plastic cap will bend into a pretzel. (I’ve seen it all!) For cookie batter, you need the METAL cap AND the cookie paddles. If you have the cookie paddles already, all you need is the metal cap.
Clear?