Most soldiers refer to them as clusters but they are technically referred to as appurtenances and they are not all created equal.
There are 3 sizes:
(1) 13/32" for full size medals
(2) 5/16" for ribbons (10/32")
(3) 7/32" for miniature medals
AR 670-1, dtd 3 Feb 2005
29–12. Wear of appurtenances
a. Oak leaf clusters.
(1) A bronze twig of four oak leaves with three acorns on each stem is worn to denote award of second and succeeding awards of decorations (other than the Air Medal), the Army Reserve Components Achievement Medal, and unit awards. A silver oak leaf cluster is worn in lieu of five bronze oak leaf clusters. It is worn to the wearer’s right of a bronze oak leaf cluster and to the left of the “V” device. Oak leaf clusters, 5/16 inch in length, are worn on service ribbons, the suspension ribbon of miniature medals, and unit awards. Oak leaf clusters, 13/32 inch in length, are worn on the suspension ribbon of full-size medals. Oak leaf clusters 5/16 inch in length, joined together in series of two, three, and four clusters, are authorized for optional purchase and wear on service ribbons and unit award emblems. Personnel wear oak leaf clusters centered on the service ribbon and suspension ribbon, with the stems of the leaves pointing to the wearer’s right. If four oak leaf clusters are worn on the suspension ribbon on either full-size or miniature medals, the fourth one is placed above the middle one in the row of three. No more than four oak leaf clusters can be worn side-by-side on service ribbons.
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h. Ten-Year device. The Ten-Year device is an hourglass that is worn centered on the suspension ribbon or serviceribbon of the Armed Forces Reserve Medal to denote each succeeding 10–year period in addition to, and under thesame conditions as prescribed for the award of the Armed Forces Reserve Medal. If two or more devices areauthorized, they are placed side-by-side. A bronze device denotes the completion of the first 10–year period (10 years); a silver device denotes completion of the second period (20 years); a gold device denotes completion of the third period (30 years), and a gold device followed by a bronze device denotes completion of the fourth period (40 years). The Ten-Year device, 11/32 inch in height, is worn on the suspension ribbon of full-size medals and on the service ribbon; the Ten-Year device, 3/16 inch in height, is worn on the suspension ribbon of miniature medals.
Vanguard sells the 5/16 ribbon attachments
Ira Green
Precision Medals: sells 13/32 medal appurtenances
Ira Green
Precision Medals: sells 13/32 medal appurtenances
