German silver submarine observation watch with special dial Circa 1942

WW II watch with marking of German Navy
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A World War II submarine observation watch with special dial, made by A. Lange & Söhne in Glashütte, Sachsen Germany, circa 1943. The numbered open faced case of this watch was crafted from silver and has the naval application number and the marking of the German Navy on the back. The original extremely rare self luminous enamel dial has Arabic hour numerals, a subsidiary seconds dial at 3 o’clock, a power reserve dial at 9 o’clock and  blued steel hands. The numbered movement has an anker chronometer escapement with a fine adjustment.
Case and movement have matching numbers and cuvette and movement signed.
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Diameter: 60 mm
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Weight: 168 g
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Signed: A. Lange & Söhne, Glashütte i. Sa.
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These special and rare A. Lange & Söhne deck watches were designed for use on submarines.