28 mm diameter, 7.77 grams (120 grains), plain edge.
1927, 1941 Bronze alloy (95.5% copper, 3% tin, and 1.5% zinc)
1942, 1945 War time bronze alloy (97% copper, 2.5% tin, and 0.5% zinc)
1946, 1947 Bronze alloy (95.5% copper, 3% tin, and 1.5% zinc)