The Omega CK 2639 is a vintage timepiece first introduced in 1949. This model was known for its generously sized case for the era, approximately 36mm in diameter, and for its variety of dial designs. It is powered by a manual winding movement, typically the caliber 265 or 266, which is a descendant of the famous 30T2 caliber. The stainless steel case features a screw-in case back which, at the time, provided water resistance up to 30 meters, marketed with the term "Swimm-proof". The specific model for sale by R.Rubini features a black dial with Arabic numerals.