The NATO standard designation for these vessels is DDG, while destroyers which have a primary gun armament or a small number of anti-aircraft missiles sufficient only for point-defense are designated DD.Nations vary in their use of destroyer D designation in their hull pennant numbering, either prefixing or dropping it altogether.Guided-missile destroyers are equipped with large missile magazines, with modern examples typically having vertical-launch cells.This is especially true for navies that no longer operate cruisers, so other vessels must be adopted to fill in the gap.Many guided-missile destroyers are also multipurpose vessels, equipped to carry out anti-surface operations with surface-to-surface missiles and naval guns, and anti-submarine warfare with torpedoes and helicopters.