Cal. 3156 is an automatic movement with day and date wheels produced by Rolex since 2008. It was used in the oversized Rolex “President” Day-Date II watch, Ref. 218000, from 2008 through 2015. This movement was part of the Parachrom family and featured the Parachrom hairspring and Paraflex anti-shock device. When Rolex updated the Day-Date, becoming the Day-Date 40 in 2015, it received the new Chronergy family Cal. 3255.
- 2008-2019 Rolex Day-Date II, Ref. 218000
As oversized watches became popular in the 2010s, Rolex created a group of special oversized movements. Cal. 3132, 3136, 3156, and 3187 all have a 2.5 mm wider main plate, bringing the movement dimension to 30.97 mm. This is not well-documented, and many sources list these movements at the Rolex standard diameter of 28.50 mm. The difference is obvious at a glance, however, with the wider flange visible in Rolex promotional shots and in the watches themselves. This larger size allowed the date wheel to be enlarged, moving the date display 1 mm further from the center on the large Datejust II and similar models.