While the outgoing caliber 4130 had been quietly updated over the years it was still a 23-year-old movement
link in need of Rolex's latest technology. Among other technical upgrades Rolex has reduced the number of components in the new
link caliber 4131 added its more efficient Chronergy escapement and added more ball bearings
link to the rotor. The Daytona still has a 72-hour power reserve.