Marine Chronometer Hamilton Winding Key -- Elgin, Mercer, U. Nardin

New old stock WWII era Hamilton Marine Chronometer Winding Key  - suitable for use with Hamilton, Elgin, Mercer & U. Nardin marine chronometers.  This NOS Marine Chronometer Winding Key came from a now-closed chronometer shop in New York City and was manufactured in the early 1940s for the Hamilton model 21 and Elgin model 600 Marine Chronometers.  These chronometers were manufactured as part of the war effort for the United States Navy.  The winding key is approximately 3 1/2 inches in length and features a ratcheting mechanism to keep the chronometer from being wound in the wrong direction.   The quality of construction is superb as would be expected. The key is also suitable for modern (20th century) Mercer and Ulysse Nardin marine chronometers as well. The Marine Chronometer Hamilton Winding Key is supplied as shipped to Hamilton and Elgin Watch companies during World War II.