It took Rolex over five years to develop an in-house quartz movement that the manufacture could be proud of, and in 1977, the Oysterquartz was born. The calibers 5035 (with date) and 5055 (with day and date) were indeed impressive, allowing for fine tuning and regular servicing like their mechanical predecessors. The initial Oysterquartz watches did not carry COSC certification; watches produced from late 1978 until the retirement of the Oysterquartz line in 2001 featured this certification.
It took Rolex over five years to develop an in-house quartz movement that the manufacture could be proud of, and in 1977, the Oysterquartz was born. The calibers 5035 (with date) and 5055 (with day and date) were indeed impressive, allowing for fine tuning and regular servicing like their mechanical predecessors. The initial Oysterquartz watches did not carry COSC certification; watches produced from late 1978 until the retirement of the Oysterquartz line in 2001 featured this certification.