Reference: CK 2998
Year: 1959
Movement: Manual winding (mechanical)
Caliber number: 321 (17 jewels)
Created in 1946
Formerly called "27 CHRO C12 T2"
Used on first generation "moon watches"
Function: Tachymeter, Chronograph
Case: Stainless steel
Case back: Screw-in
Dial: Matt black with luminous hour markers and luminous "Alpha" hands (radium), with applied OMEGA-logo.
Crystal: Hesalite
Bracelet: Stainless steel; reference number 7077 or 7912
Water resistance: 50 meters

More product information

2nd "Speedmaster" watch after CK 2915 (1957)
Case : 40 mm diameter, push-buttons with "O" gaskets, screw-in case back with "O-ring" gasket.
Bezel : stainless steel with inserted black aluminium tachometer ring (flat).
Size between case lugs : 19 mm
International Collection : 1958-1962
Swiss retail price (1960) : CHF 420.-

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

PS: I have since acquired a bracelet ref 7077 for it! Woohoo!!