Speedometer lens retainer used on the inside of the cluster bezel to shield the face of the gauge. Will show a minor amount of wear or rust, plan on cleaning it up and possibly repainting. Almost the same as the Tachometer lens retainer, tachometer version has a clipped section shaped like a thumb nail on the edge. Ford called these retainers a 'mask'.
Stamped C7WF-10894-S or C8WF-10894-S. Also C7WY-10890-
NOTE: The speedometer retainer is different from the tach retainer, the tach retainer is notched for the screw post in the bezel.