Rolex developed an entirely new watch movement series in the 1970s, sharing the same basic gear train between conventional automatic and quartz models. The resulting Cal. 3035 and Cal. 5035 were launched in 1977. These movements were much enhanced from previous Rolex offerings, operating at a modern 28,800 A/h and featuring quickset date advance. The hairspring has a Breguet overcoil and Microstella regulation.