5/8" with raised lettering around enamel colors at center representing Mexican flag. Tiny luster loss mostly off the reverse. Front displays Exc. The pin was produced in response to the US Army, under Wilson's order and at the direction of John J. Pershing (see next item) who launched an expedition into northern Mexico to find and capture Mexican revolutionary Pancho Villa who had attacked the American border town of Columbus, New Mexico. See two previous U.S./Mexico items. Rare.