The Kommandogerät (command control computer) 40, known as a Director, was a German optical range finder used principally for large anti-aircraft guns, such as the 8.8cm Flak 36 or the 10.5cm Flak 40. By calculating the length of the tube and the angle at which the lenses were positioned, the crew could pinpoint aircraft target locations. Introduced by the German military in 1941, this Director was utilized by all three services and could be modified for use with almost any anti-aircraft gun. The Kommandogerät was run by an analog computing system. Analog computers store and transmit data in a continuous form of physical quantities and perform calculation with the help of measures. It is quite different for the digital computer, which makes use of symbolic numbers to represent results. This was considered one of the most technologically advanced range finder of the time.

In the field, the Director required a 5 man crew; two men to input azimuth and elevation data, a third man to set the slant range by means of a 4 meter stereo range finder mounted on top of the Director, a fourth man to set the horizontal angle of approach, and a fifth man as general operator.

By calculating the length of the tube and the angle at which the lenses were positioned, the crew could pinpoint where the target aircraft was with great efficiency. Using the Director, the time from acquiring a target to firing the first round could be achieved in less than 30 seconds. A slant range of up to 18,000 meters (11.1 miles) or an aircraft altitude of 39,000 feet could be targeted. For transport, the Director is mounted on a special trailer, equipped with lifting devices and towed by a light truck. This Kommandogerät 40 is believed to one of three that remain in existence. It is displayed in the American Heritage Museum’s “Defense of the Reich” exhibit.