Omega, Speedmaster, Jubilee 27 CHRO C12, "Limited Edition", chronograph, ca 1992.

In the year 1942, Omega introduced their first chronographs featuring the caliber 27 CHRO C12. The movement was further developed and renamed caliber 321, powering several models including all Speedmasters until 1968. Fifty years later, in 1992, Omega commemorated the jubilee of this legendary movement with a limited edition release. The exclusive edition, consisting of only 999 units, featured yellow gold cases, a caliber 863 movement, and, for the very first time on a Speedmaster, a sapphire-crystal. Each watch was presented in a specially crafted wooden box.