This is a great looking US NAVY - USS Sierra (AD–18) challenge coin. Coin has reeded edges and is about 1 9/16" in diameter. Front side of coin is printed and colorized while the rear side is raised lettering and gold plated. Coin is contained in an acrylic air tight holder.

USS Sierra (AD-18) The second U.S. Navy ship to bear the name, Sierra was laid down on 31 December 1941 by the Tampa Shipbuilding Company of Tampa, Florida; launched on 23 February 1943; and commissioned on 20 March 1944,

On 18 May, Sierra stood out of Norfolk en route to San Diego, California, via the Panama Canal Zone. She was in San Diego for five days and, on 7 June, departed for Pearl Harbor. The destroyer tender rendered services to destroyers and destroyer escorts at Pearl Harbor from 13 June to 3 September 1944.

With the need for fleet repair units at advance bases to support the forthcoming invasion of the Philippine Islands, Sierra proceeded to Seeadler Island, Manus Island, Admiralty Island. She was attached to the United States third Fleet and serviced its ships until February 1945. Her most outstanding accomplishments were the replacement of a complete 5-inch (127-mm) gun mount on the battleship USS California (BB-44) and rebuilding the starboard stern of the destroyer USS Claxton (DD-571) , which had been severely damaged by a Kamikaze in Leyte Gulf.

Sierra was the oldest active duty warship prior to her decommissioning. As such, she was entitled to fly the "Don't Tread on Me" flag denoting her as such.

Sierra was decommissioned on 15 October 1993 and was sold for scrapping.