USS San Diego (LPD-22) Amphibious Transport Dock Challenge Coin – “Semper Vigilans” Up for sale is a unique, shield/bow-shaped challenge coin from the USS San Diego (LPD-22). This beautifully crafted coin features a distinct geometric design representing the vessel, celebrating both the United States Navy and Marine Corps personnel who serve aboard. A highly collectible piece for military coin enthusiasts, veterans, or active duty service members. Item Details: Front Side A – image_5. It proudly displays the interlocking “SD” logo at the top with the hull number “22” on both sides. The lower section features two colored enamel inserts: the official US Navy emblem on the left and the US Marine Corps (Eagle, Globe, and Anchor) emblem on the right. Back Side B – image_6. The text “USS SAN DIEGO” is raised at the top, with “LPD 22″ boldly displayed at the bottom. Condition: Good/Used condition with a beautiful aged patina (please review the photos closely for exact cosmetic condition).