The Datejust 31 is a smaller version of the Datejust, traditionally called 'boys-size'. Its case measures 31mm across and is available in a great number of configurations and materials. It is powered by caliber 2235.
This model is equipped with calibre 2235, a self-winding mechanical movement entirely developed and manufactured by Rolex. Like all Rolex Perpetual movements, the 2235 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