2018 $5 Coloured Fine Silver Proof Triangular Coin, Land-Sea-Air. Comprised of the Australian Army, the Royal Australian Navy and the Royal Australian Air Force, the Australian Defence Force is the tri-service military organisation responsible for the defence of the nation by land, sea and air. Since Federation in 1901, Australians have committed themselves in arduos and dangerous conditions, in conflicts that include the Boer War, the First and Second World Wars, Korea, Malaya, Vietnam, Iraq and Afghanistan, and have participated in nearly one hundred peacekeeping operations since the first in 1947. Mintage 10,000. Certificate of Authenticity is included. Please contact Adelaide Exchange Jewellers to find out more on this item.