Currently working and was tested over a 19 hour period and kept near perfect time, lost approx 10 seconds. It may need a service to keep absolute perfect time. The 10k gold filled case is 50.8mm in diameter. 1939 Hamilton, Grade 992E, Model 2, 21J, 16S, lever set, stem wind, Elinvar Hairspring, double roller, railroad grade, double sunken dial, 5 adjustments, gold screw setting with date serial number 2637947. Only 63,900 of this model were made in 1939 making it scarce. Nice dial, perspex is very cloudy, replacing it will make the appearance of the pocket watch far better.