Authorized on February 19, 1939, and awarded to officers and enlisted personnel of the U.S. Marine Corps Reserve who, subsequent to July 1, 1925, have fulfilled certain designated military service requirements within a four year period of service in the Organized Marine Corps Reserve. (This medal was originally awarded for service in the Fleet Marine Corps Reserve. The first medals issued had the words "Fleet Marine Corps Reserve" on the obverse, and are quite rare).