A Non-Commissioned Officer Development Ribbon is an award issued by the UNSC (based on the US Airforce branch) to recognize those non-commissioned officers who have completed a prescribed leadership course at an NCO training school. It is seen on Captain Keyes's ribbon rack.
The NCO Professional Military Education Graduate Ribbon is issued by the United States Air Force currently, and is awarded for completion of proscribed non-commissioned officer professional development programs. Such programs include Airman Leadership School (ALS), Non-Commissioned Officer Academy (NCOA), and the Senior Non-Commissioned Officer Academy (SNCOA). Additional awards of the NCO Professional Military Education Graduate Ribbon are denoted by oak leaf clusters.