along with Reconnaissance Gruppen (Groups). The Geschwader could be either fighter or bomber units. Depending on the nature or purpose of the Fliegerkorps, it would have only bomber or fighter units. Similar to the Luftflotte, a Fliegerkorps also had an adjutant as well as other departments. However, it did depend on the parent Luftflotte for administrative and supply purposes. The Fliegerkorps were numbered consecutively in Roman numerals. During the initial organization of the Luftwaffe, it was divided into Fliegerdivisionen. However, during later reorganizations, most of these were replaced by the Fliegerkorps. Some remained in operation on the Eastern Front. A Jagdkorps was a more specialized version of a Fliegerkorps with limited responsibility to fighter command only. A Jagd-Division was subordinated to a Jagdkorps but specialized in fighter operations. Jagd-Divisionen (fighter divisions) were active at one point or other during this period. Together the fighter force of Luftwaffe was also called Jagdwaffe. The Luftwaffe also had specialist units of varying sizes for testing new aircraft as well as captured Allied machines – these units could be as small as a Staffel, or as large as a Gruppe. It was initially unnumbered and simply called the Lehrdivision (Instruction Division) but in later years several Erprobungskommando units of varying size were created to test specific new aircraft, usually numbered with the RLM aircraft designation system airframe number matching the aircraft they were meant to test. Along with the aircraft test and evaluation, a Lehrdivision was also responsible for testing anti-aircraft defenses and air signals equipment. The staff of this division were required to have prior combat experience. The Lehr units in this division were usually made part of operational units, receiving help from them for testing under combat conditions. Unlike the Erprobungskommando units, a Lehrdivision did not undertake the testing of experimental aircraft. As the war went on, some of the units under its command were used for operational purposes. Tactical level Geschwader In the Luftwaffe the largest mobile and autonomous unit was the Geschwader. A Geschwader was the equivalent of a Wing in the United States Army Air Forces (USAAF). It would be used for different purposes such as bombing, interception (both single and twin engine), ground attack and reconnaissance. A Geschwader would be named, based on its purpose. There were several Geschwader with the same purpose. They would be named with an Arabic numeral following the word. It was also customary