Reference: CK 2913
Year: 1958
Movement: Automatic (mechanical)
Caliber number: 500 / 501
(Cal. 500 - Created in 1955 with 17 jewels)
(Cal. 501 (sometimes chronometer)- Created in 1955 with 19 jewels)
Case: Stainless steel
Case back: Screw-in
Dial: Black dial with superluminous white hour markers and "broad arrow" luminous hands (radium). (Also comes in the very rare 'gilt dial' as you see here)
Crystal: "Triple layer" domed armoured hesalite
Bracelet: Stainless steel (ref 7077 or 7912)
Water resistance: 200 meters

More product information

Case : round (39 mm diameter), with special "NAIAD" crown, screw-in case back with "O'ring" gasket, stainless steel rotating bezel with black "0-60" scale and luminous marker, SS bracelet (ref. 7077).
Size between case lugs : 19 mm
International Collection : 1958-1962
Swiss retail price (1959) : CHF 360.- (on bracelet), CHF 320.- (on leather).

(Information courtesy of Omega Vintage Watches Information at www.omegawatches.com)

PS: I have since found a NOS crystal and now it looks absolutely stunning! (the last 3 pictures are with the NOS crystal) I also have acquired a bracelet ref 7912 for it!