Fig.09-2

When the inner cap is inserted into the cap tube, the notches and the protrusions (see Fig.9-1) engage to hold the inner cap in place. When the clip is placed on the cap tube, the protrusion (blue arrow) engages with the base of the clip, and the clip doesn't rotate around the cap tube. Screwing on the crown ring in this position secures the cap tube, inner cap, and clip firmly in place.