German nickel keyless lever with power reserve Circa 1942

Deck watch made for the Kriegsmarine Observation Service 
–
A fine German nickel open faced keyless lever deck and pocket chronometer with power reserve indication made for the Kriegsmarine Observation Service, by A. Lange & Söhne, circa 1942. Frosted gilt ¾ plate movement, 17-jewels, straight-line lever escapement, Guillaume balance, blued steel Breguet balance spring with patent stud fastening, swan-neck micrometre adjustment to the regulator. Hinged stainless steel cuvette. Brushed, silvered dial with painted black Arabic numerals, outer minute track, subsidiary seconds at 3, power reserve indication at 9 and original blued steel spade hands. Polished case, the back engraved with the Observation Service number. Dial, cuvette and movement signed.
–
Diameter: 60 mm
–
Signed: A. Lange & Söhne Glashütte/SA