Currently working and was tested over a 21 hour period and kept near perfect time, may have lost 10 seconds. It may need a service to keep absolute perfect time. The 10k gold filled case is 50.3mm in diameter. 1953 Hamilton, Grade 950B, Model 6, 23J, 16S, lever set, stem wind, railroad grade, 6 adjusts, double sunken dial, Montgomery dial, Railway Special with date serial number S20946. Scarce, only 32,500 of this model was produced during 1953. Dial has a scratch between 1 & 2 and needs a clean. Very nice case, tiny dent to case back.