German silver military deck watch of the navy Circa 1942

Silver naval anker chronometer 
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An unusual 2^nd World War military deck watch of the German Navy made by A. Lange & Söhne in Glashütte, Germany, circa 1942. The original case of this watch was crafted from silver. It is engraved on the back with the German eagle and the German Navy 1^st Class mission number M157. The white enamel dial features Arabic hour numerals, an outer minute track, subsidiary seconds at 6 o’clock and blued steel spade hands. The numbered movement is equipped with an anker chronometer escapement and fine adjustment.
The case and movement bear matching numbers, and the dial and movement are signed.
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Diameter: 60 mm
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Weight: 138 g
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Signed: Deutsche Uhrenfabrikation Glashütte SA. A. Lange & Söhne