The widely used Super-Dreadnought ejector combined a large ejector with two small ejectors in one. Some firearms have no ejectors, only extractors, requiring the user to manually remove spent cartridges. Vacuum itself is maintained by steam ejectors. The leaked solution was safely recovered into primary containment using originally installed steam ejectors. The engine cooling airflow is intensified by means of two specially designed ejectors. Two are carried on board and can be fired from the submerged signal ejectors. It also, has ejectors that automatically expel spent shells. Typically two ejectors are fitted, large and small. Unlike its predecessor, it has ejectors that automatically expel spent shells. Bis-Thiadizolbenzene-1,2-diamine (NV038) is one of the newer zinc ejectors. Smoke ejectors may also be used for this purpose. The forward-facing ejectors blow away detritus during taxi. Many engines were also equipped with Giesl ejectors.