This is a historically significant medallion from one of the greatest Navy shipyards in the World. One side depicts Mare Island Naval Shipyards established in 1854 with their logo. The opposite side depicts the Decommissioned 1st nuclear powered submarine USS Nautilus SSN-571 for the U. Navy that took place at Mare Island. Many tremendous events in Navy history happened at Mare Island. This medallion is a tremendous piece of Navy history. This medallion indicates and honors the USS Nautilus was decommissioned at Mare Island, but I don’t know if this coin was handed out in the date of decommissioning or just honoring that event. Either way, it’s very rare and cool. It measures approximately 2 in diameter and has a designed hole placed in the medallion. It shows light scratches, light edge dings, and some discoloration from use/display over the years. The metal appears to be maybe brass or some other metal. Please review pictures provided for details of condition and please ask any questions before purchasing.