Australian Defence MedalAustralian Defence Medal Full size medal Unmounted with 15cm ribbon as required for swing mounting. Miniature size medal Unmounted with 10cm ribbon as required for swing mounting. The Australian Defence Medal recognises Australian Defence Force personnel who have efficiently completed either: an initial enlistment period, or four years service, whichever is the lesser, and all of the relevant service was after 3 September 1945. Included are former