Currently working and was tested over a 15 hour period and kept near perfect time, maybe gained 10 seconds. It’s possible it may need a service to keep absolute perfect time. 1930 Hamilton, Grade 992E, Model 2, 21J, 16S, lever set, stem wind, 5 adjusts, gold screw set, railroad grade, double roller, Elinvar spring, only 63,900 made of this model during 1930 with date serial number 2587569. The 10k gold filled case is 50.6mm in diameter. Very nice dial, case back has only minor wear and a few dull dents. A very nice pocket watch !!!