In 1942 the first Omega chronographs equipped with the caliber 27 CHRO C12 were marketed, which later evolved and was later renamed caliber 321. As such it equipped several models, including all Speedmasters until 1968. Fifty years on, this 1992 limited edition pays tribute to it. The model, produced in 999 pieces, features a yellow gold case, caliber 863 and, for the first time in a Speedmaster, sapphire crystal. It came in a special wooden case. (Credit: Moonwatch Only, A. Marquié)