Hamilton Time Stamp Watch from periscope camera with UDT waterproof outer crown and safety chain. Overall deminsions are 3.6 inches long x 1.73 wide x .35 thick  solid Aluminum in black anodized finish in very high condition. Has eight screw bezel with waterproof gasket and glass crystal. Dial is style approved for Atomic submarine service all hands are painted white (non radium) and print is also white paint (non radium). Radiation sensors were so sensitive the radium dials would set off detection alarms. Nuclear subs were built beginning in the early 50's many produced at the Mare Island Naval facility in San Fransisco.  First nuclear submarine built there was the USS Sargo which our government authorized in 1955 and was completed in 1957.  First one of these Hamilton time stamps I acquired was in Los Angeles and the story about the time stamp watch referred to it coming through the Mare Island facility which serviced and then had many decommisioned subs there waiting disposition.  Movement in the timer is a Hamilton caliber 735A with 18 jewels .....I have inspected 5 of these over the years and none of the movements had serial numbers on them. Research indicates the commercial Model 735 was produced initially around 1955 so my best guess the military 735A was as well. Serial numbers I've seen started around 1000 and the highest was 1390. Ordinance Part No. 39360 and Serial  Number 1351 on this timer. Watch Housing Assembly, Pt. No. 39360-2-01, Stk No. 6400-192855, Mfg. By Hamilton Watch Co. for: Edgerton, Germeshausen & Grier, Inc. ...some of the other timers had this information on a tag affixed to back...tag is not on this one. All three names were MIT graduates who supported the war effort then formed a defense contracting firm in 1947.  Edgerton was the father of high speed photograhy and participated in many special government projects.