Korean Destroyer eXperimental
KDX (Korean Destroyer eXperimental) is a substantial shipbuilding program embarked on by the Republic of Korea Navy. It is a three-phased program consisting of three individual classes of ships: KDX-I (3,800 tons), KDX-II (5,500 tons), Aegis-equipped KDX-III (10,000 tons).
Source: Wikipedia — Korean Destroyer eXperimental (CC BY-SA 4.0)