Federation freighters, like Federation merchant ships, were specialized starships utilized by the Federation for hauling freight. These vessels encompassed a variety of designs, and were often operated with little or no crews. Manned vessels, both of the 23rd and 24 centuries, were often used for transporting more valuable cargo, such as deuridium or dilithium crystals. (TAS: "The Pirates of Orion"; DS9: "The Passenger")