| Brand | Rolex |
| Caliber Number | 3255 |
| Movement Type | Automatic |
| In-House | Yes |
| Jewels | 44 |
| Total Parts | 201 |
| Power Reserve | 70 hours |
| Vibrations Per Hour | 28,800 |
| Hacking | Yes |
| Rotor Direction | Bidirectional |
| Balance | Paramagnetic Oscillator |
| Shock System | Paraflex |
| Hairspring | Parachrom Blue |
| Features | Hours, minutes, small seconds, central chronograph seconds, 30 minutes counter, 12 hours counter |
| Country of Manufacture | Switzerland |
| Known Models | Rolex Day-Date 40 |
Originally announced at Baselworld 2015. Rolex claims the new caliber 3255 is two times more precise than an officially certified chronometer. The technology within is protected by 14 patents acquired by “The Crown”. One of the patents includes the Paramagnetic Oscillator with new balance staff that offers enhanced resistance to magnetism.
From Rolex.com:
Calibre 3255’s criteria for precision in everyday wear are twice as exacting as those for an officially certified chronometer. It incorporates the new Chronergy escapement patented by Rolex, which combines high energy efficiency with great dependability. Made of nickel‑phosphorus, it is also insensitive to magnetic interference. The oscillator, the true heart of the watch, has an optimized blue Parachrom hairspring, which is also up to 10 times more precise than a traditional hairspring in case of shocks. Thanks to a new barrel architecture and the escapement’s superior efficiency, the power reserve of calibre 3255 extends to three days. This means the watch will easily continue to run from Friday evening into Monday afternoon even if not worn or wound. -Rolex