 While the Datejust 41 has a similar-sized 41mm diameter case as the Datejust II, the Datejust 41 has smaller indexes and a thinner bezel compared to the Datejust II.In this year, Rolex also introduced the new Caliber 3235 movement, which replaces more than 90% of the parts of its predecessor, the Caliber 3135 - Rolex’s longest running and most successful movement.Caliber 3235 includes a new escapement, the Chronergy, along with other significant improvements, and provides a 70-hour power reserve while maintaining the same dimensions as its predecessor.