to calculate the correct angles, as on the earlier CSBS models, but then fed them directly into a remote sighting unit, the sighting head. This provided practically instant updates of the sighting angles. The wire sights of the earlier models were replaced by reflector sights indicating the location the bombs would hit if dropped at that instant. As the sighting head lacked the vector computer it was much smaller than earlier models, which allowed it to be easily mounted on a stabilized platform. This allowed the sights to be used even while the aircraft was maneuvering, and required only 10 seconds to settle. Together, these changes dramatically simplified the task of maintaining an accurate bombsight setting. On the downside, it required the addition of a new crew member to operate the system. This was not a minor problem as most aircraft had no room for them. This led to the ultimate development of the series, the Mk. XIV. This version replaced the manual input dials with ones powered by air suction bled from the engines. Before the mission, the bomb aimer entered basic information about the target altitude and the bombs being dropped, and periodically updated the wind speed and direction. Everything else was fully automated. Versions were also developed that replaced the altitude measurement with a radar altimeter for low-altitude use, but these Mk. XV and Mk. XVII were not used operationally. The Mk. XIV was a major advance over the Mk. IX, but service entry was slow. It was not until January 1942 that it was given priority. This was aided by Sperry Gyroscope, who re-designed the system to U.S. production methods. They sub-contracted construction to A.C. Spark Plug who built tens of thousands as the Sperry T-1. It did not offer the level of accuracy of tachometric bombsights like the Norden or ABS, but for night area bombing from medium altitude as practiced by RAF Bomber Command this was not an issue. The Mk. XIV remained in RAF use until 1965. SABS Later in the war the development of the Tallboy and Grand Slam earthquake bombs demanded accuracy that even the Mk. XIV could not supply. For this role, the Automatic Bomb Sight was dusted off and mounted to new stabilization platform, producing the Stabilized Automatic Bomb Sight. This complex device was available only in very small numbers from late 1943 on, and used only by specific