I made these plugs to fit the window frame on my Therma-Tru fiberglass entry door, which I had to disassemble in order to replace the weatherstripping around the window insert.  I permanently damaged the original plugs while extracting them and these plugs were a good replacement, matching the contours nicely.  These plugs can be extracted by carefully drilling a small hole in the center and then inserting a screw to extract them.  The flush install tool isn't necessary, but it can make installation easier.