A. Lange & Sohne original WWII Luftwaffe Beobachtungsuhr, or B-uhr, Type B navigator's watch. Case diameter 55mm. Movement: Lange & Söhne cal. 48/1. Marked on the back with FL 23883 (FL = flight, 23 = navigation). Regulated and tested chronometer. As Luftwaffe property, they were issued to observers before a flight and returned upon landing. Approx. 1,200 were made before watch factory was bombed to rubble.