<Tr> <Td> </Td> <Td> Air Force NCO PME Graduate Ribbon </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> Air Force Training Ribbon </Td> <Td> </Td> </Tr> <P> Except for the Air Medal, unique decorations and awards issued by Department of the Army or Department of the Air Force, and those decorations and awards issued by the Department of Defense, the other uniformed services use ​ ⁄ inch stars to indicate subsequent personal decorations only; a gold ​ ⁄ inch star is equivalent to a bronze oak leaf cluster, while a silver ​ ⁄ inch star is equivalent to a silver oak leaf cluster . While the Air Force uses oak leaf clusters for the Air Medal, since the Vietnam War, the Army has used ⁄ - inch (4.8 mm) bronze Arabic numerals to denote subsequent awards, in which case the ribbon denotes the first award and numerals starting with the numeral "2" denote additional awards . </P> <P> In other nations, oak leaf clusters are also used as symbols for various awards and decorations . In Germany, the German oak is the national tree of Germany, thus oak leaves are a prominent symbol on most German military orders . During World War II, the Knight's Cross of the German Iron Cross could be awarded with the additional distinction of oak leaves (mit Eichenlaub). Of the 7,313 awards of the Knight's Cross, only 882 received oak leaves . After World War II, Iron Crosses awarded previously could be worn by the recipient provided the swastika was replaced by oak leaves . The Bundeswehr awards the Cross of Honour for Bravery for extraordinary bravery . The Cross of Honour for Bravery differs from the Badge of Honour by an adornment in the shape of stylized double oak leaves . Furthermore, it was featured on the Pfennig in Germany and since the introduction of the euro in 2001 it is used on the obverse side of the German euro coinage . In earlier times, the Pour le Mérite, the highest military order in the Kingdom of Prussia, could also be awarded with oak leaves . A civil version of the order, for accomplishments in the arts and sciences, still exists in the Federal Republic of Germany . </P>

When are you authorized to wear two of the same ribbon