The Kidd-class guided missile destroyers - DDGs- were a series of four destroyers based on the Spruance class destroyers. The Kidds were designed as more advanced multipurpose ships, in contrast to their former ship's class focus on anti-submarine warfare, adding considerably enhanced anti-aircraft capabilities. Originally ordered for the former Imperial Iranian Navy, the contracts were canceled when the 1979 Iranian Revolution began, and the ships were completed for the U.S. Navy. They were equipped with heavy-duty air conditioning and other features that made them suitable in hot climates, they tended to be used in the Middle East, specifically the Persian Gulf itself. During their service with the U.S. Navy from 1980s to the late 1990s, the ships were popularly known as the "Ayatollah" or "dead admiral" class. They were decommissioned and sold to Taiwan, now being known as the Kee Lung-class.