Yacht-Master II calibre 4161

Summer is continuing with a photo of impressive Rolex calibre 4161. It's breathtaking that Rolex engineers devoted 35.000 hours to developing this complication.

For the Yacht-Master II, Rolex devised a new and unique horological complication: a programmable countdown with a mechanical memory and on-the-fly synchronization, designed speciffically for the start sequence of nautical regattas.