The earliest movement used in the Rolex Explorer II was the Caliber 1575, but over the years it was replaced with more technically advanced movements to help this watch reach its full adventure potential. The first big upgrade was the Cal. 3085 which allowed the 24-hour hand to be adjusted independently from the 12-hour hand. This meant the Explorer II no longer just indicated day and night hours, but could also be used to track a second time zone – turning it into a GMT watch. Then came the Cal. 3185 which was improved upon more with a Glucydur balance wheel that is not only paramagnetic but was resilient in extreme temperatures. The 3186 came next with a blue Parachrom hairspring that is anti-magnetic and shock resistant for even better durability. Finally, we have the modern-day Cal. 3187 which features all the upgrades this watch has gained over the years – from the GMT functionality to the blue Parachrom hairspring. It’s also notable for its high-performance Paraflex shock absorbers, 31 jewels, -2/+2 seconds per day accuracy and 48-hour power reserve.The Submariner has a much longer history, so we’re going to start with the automatic Caliber 3135, which, while upgraded over the years, has been used in all date-displaying Submariner watches since 1988. While the aesthetics of the Submariner can vary, the Cal. 3135 has remained a trusted source of power for this beloved timepiece because of its sheer reliability. Today, the upgraded Cal. 3135 movement is COSC certified, outfitted with the anti-magnetic and ultra shock-resistant blue Parachrom hairspring, and boasts an impressive 48-hour power reserve just like the Explorer II.
