Unissued genuine U.S. Army hot weather field cap OG-507, new old stock post-Vietnam War, DLA contract number indicating it was made in 1987, known as the 'Ball Caps' and are a 2nd issue style that originally started being issued in 1970 and have a synthetic sweatband and a front stiffener. We have these in a 7 1/8 size (56.8 cm).