Mechanism: Self-winding movement, bi-directional winding, 28,800 A/h, 31 jewels, Glucydur balance wheel with Microstella weight screws, newly developed Parachrom blue Breguet hairspring, newly developed Paraflex Antichock system, date and day of week indication.

Designed for and introduced with the 2008 Day-Date II model. The Day-Date II is equipped with the calibre 3156, a selfwinding mechanical movement entirely designed and manufactured by Rolex. It features a day and date calendar disc mechanism. The 3156 is fitted with a Parachrom hairspring and high performance Paraflex shock absorbers developed by Rolex, offering greater resistance to shocks and to extreme conditions. Like all Rolex Perpetual movements, the 3156 is a certified Swiss chronometer, a designation reserved for high-precision watches that have successfully passed the Swiss Official Chronometer Testing Institute (COSC) tests. Its architecture, in common with all Oyster watch movements, makes it singularly reliable.

Family Notes: For over fifty years, the Rolex President was exclusively available with a 36mm case. For some, this was too small for a men’s watch, even for a dress timepiece. So in 2008, the Swiss watchmaker unveiled a much larger Rolex President with the Day-Date II. Then, seven short years later, Rolex introduced yet another version of the Presidential watch with the Day-Date 40, which in fact replaced the President II. Today we explore the differences and similarities between the Day-Date II and the Day-Date 40 so you can determine which Rolex President is the right fit for you.

On paper, the Oyster case of the Day-Date II watch measures 41mm while the Day-Date 40 measures 40mm (Who would have guessed?). Although on the outset the 1mm difference may seem trivial, wearing the watch is a different story. Due to its thicker lugs, chunkier build, and wider bezel, the Day-Date II fits much larger than the 1mm variance suggests.