Rolex Day-Date President 6612

The Reference 6612 is the smooth-bezel model from the second Day-Date series, produced for a short period from c. 1957-1959. This reference is technically significant as it housed the improved Caliber 1055 movement. This upgraded caliber featured a new free-sprung balance with Micro-Stella regulation screws, a major innovation that allowed it to meet stricter chronometer standards. This mechanical improvement earned the 66xx series the right to bear the “Superlative Chronometer Officially Certified” text on the dial for the first time. The 6612, with its 36mm gold case and smooth bezel, represents a critical step in rectifying the mechanical issues of the inaugural 65xx series and establishing the Day-Date’s reputation for superlative accuracy.