Occasionally the slots or servo openings on your foam board models need to be made a bit larger. And it is true for scratch built models or kits. This tool is handy for cleaning up or enlarging those holes. The paint stirring stick can usually be had for free at your local hardware. You may need to trim it a small amount. While you are there pick up a package of self stick sand paper. Use a finer grit, say 150 or 200.