Rolex Lady-Datejust 178240 Blue Dial 31mm Oyster Steel

The 31mm Datejust sits in the middle tier of Rolex's women's-watch range, between the 28mm Lady-Datejust and the 36mm unisex sizing. Reference 178240 is the all-steel variant of the mid-size line, introduced as part of the 1782xx family when Rolex updated the bracelet attachment and clasp architecture around 2009.

Blue sunburst dial with applied baton indices and the Roulette date wheel at 3 (alternating red and black numerals). The bezel here is fluted steel rather than smooth or diamond-set, a less common choice on 178240 since the polished domed bezel tends to be the volume seller in this size. Mercedes hands, Cyclops magnifier over the date aperture.