Authentic US Coast Guard medal for Good Conduct. Post-WWII variation with a more uniform pin device on the reverse. Good condition, nice details. 
 
The Coast Guard Good Conduct Medal (CGGCM) was authorized by the Commandant of the Coast Guard on 18 May 1921, but not designed until 1923 and originally used enlistment bars as attachments, in the same manner as the Marine Corps and Navy Good Conduct Medals.