This medal was authorized by Congress in June 3, 1898 for any Navy or Marine Corps personnel assigned to the ships of Admiral Dewey's squadron which fought in the Battle of Manila Bay. The ships involved were the OLYMPIA, BALTIMORE, BOSTON, CONCORD, PETREL, RALEIGH, McCULLOCH (a Revenue Cutter), NASHAN and ZAFIRO. It is a scarce medal so, of course, reproductions abound.
The medal was designed by renowned sculptor, Daniel Chester French (who also sculpted the statue of Abraham Lincoln in Washington's Lincoln Memorial). It was struck by Tiffany an Co. in New York and only 1,825 were issued.
The reverse side of the medal indicates the ship that the recipient served on. Also, on th medal's lower rim is name the actual name of the recipient. This is only one of two service medals issued that actually have the name of the recipient on the medal.
Service Medal Index on the Navy Historical Center Webpage at http://www.history.navy.mil/medals/dewey.htm