A Second World War German Luftwaffe Aviator's Wristwatch, RLM Nav B-Uhr, FI 23883, circa 1941, manual wound lever movement numbered 1484140 , overcoil hairspring, original finished black dial with luminous Arabic hour markers, blued steel luminous hands, large centre seconds hand, large sized nickel silver plated case with a snap-on back engraved RLM Nav B-Uhr and numbered 1157 , band of the case numbered FI 23883 , fixed bars between the lugs, onion shaped winding crown
55mm wide, The German Air Ministry recognised the need for an accurate observer's watch to navigate and assist crews on long range flying missions. These watches are known as B-Uhrs (Beobachtungsuhr or observer's watch). The watches were tested by the Deutsche Versuchsanstalt fur Luftfahrt DVL Institute. From 1941 onwards they were classified with an FI number which stands for flight and control, the 23 stands for navigation and followed by the three digit DVL number.
