This is a black 58mm Classic SD with on the front the seal of the United States Department of Defense, and on the back the signature of former Secretary of Defense William Cohen (under president Bill Clinton).
The seal of the Department of Defense: an American bald eagle, holding three crossed arrows (representing the classic three branches: army, navy and air force), above a wreath of laurel (representing honor received defending peace) and under rays and stars (representing glory).
external links: SAK Wiki DoD (Wikipedia) William Cohen (Wikipedia)