Solid Sterling Silver; Heavy Bold and beautifully detailed ring with a tapered band which makes this ring very comfortable. Made in America by a veteran one at a time in my small shop. The OS operates radar, navigation and communications in the Combat Information Center aboard combat ships. They also operate and maintain IFF, ECM and assist combat aircraft. This symbol has been around for a while. Before OS we had RD’s or Radarmen. The two rates were merged in 1972. This is a beautiful ring and would make a wonderful addition to your collection or for someone special. Show your Pride.