First Infantry Division, Ft. Riley KS, home of the Big Red One. This ring bears the victory standard on one side, Fort Riley Kansas, USA on the other side, and the Big Red One shoulder sleeve insignia (SSI) on the front. This one is scaled to a men's size 10 ring.
Other mens ring sizes can be found here:
Size 9: http://shpws.me/MD1J
Size 11: http://shpws.me/MCKe
Size 12: http://shpws.me/MCJQ
Size 13: http://shpws.me/MCJK