Several clasps were awarded with the medal. [Two claps are shown on the medal above.] The Navy and Marine Corps each had two clasps, with the "Fleet" clasp awarded for service on vessels of the fleet. The "Base" clasp was for service on shore at bases and naval stations outside the continental limits of the United States. [This included Alaska and Hawaii at the time.]
On the reverse (back) the inscription "For Service during the Limited Emergency Proclaimed by the President on 8 September 1939 or during the limited emergency proclaimed by the President on 27 May 1941" is given. Below this inscription is a spray of seven leaves.
Note: the Army had a "Foreign Service" clasp for service outside the continental limits of the United States, and the Coast Guard authorized a "Sea" clasp. Also, personnel of the Navy, Marine Corps, and Coast Guard who served on board certain vessels operating in actual combat were entitled to a bronze "A" on the medal ribbon.
References:
American War Medals and Decorations, by Evans E. Kerrigan, The Viking Press, N.Y., 1964.
The Call of Duty : Military Awards and Decorations of The United States of America, by John E. Strandberg and Roger James Bender, 1994.
Guidebook of U.S. Medals : A complete guide to the decorations and awards of the United States from 1782 to present, by Evans E. Kerrigan, Medallic Publishing, 1990.