Original, RARE, Complete WWII Directional Gyro, Electrical, Luftwaffe Fl. 22561 Kurskreisel. Used in bombers Dornier Do-17, Junkers Ju-88, and night fighter Bf 110 of the German Luftwaffe. This instrument was part of the Siemens K 4ü course control system, and could be used as a stand-alone course display system, and in conjunction with the PKS 11 patina course controller and the PDS three-rotor control system. With the left knob depressed, the gyro is caged, and released when pulled out. When rotated, it turns the lower compass card. The right knob rotates the upper compass card. An inclinometer is located just below the display to assist in coordinating turns .The bar across the top is an access door. When gently pulled down, two lamps are revealed, which would illuminate the compass cards and inclinometer.