Rotation lock, stoppers for the bathtub drain. The lower part fits, the upper not. With us only the lower stopper was broken. First. Because I had a new part for the top also, I mounted on the rotary closure which was 20 years off and went thereby broken. Unfortunately, the spare parts of Grohe (formerly Grohe also) did not fit, because the inner screw had a notch, what this cover does not fit.
