Omega Seamaster Calendar automatic ref. 2849 with date and center second. It is powered by the excellent caliber 503 with swan neck regulator.
This rare model called “big logo” (because of the large seahorse on the caseback) was produced in 1958 only. It was the first time that the seahorse medallion appeared on the case of a Seamaster.
The original cream dial has developed a nice patina. Applied indexes and logo.