Rolex Datejust 31 mm 178240WRO Steel White

The Rolex Datejust is widely regarded as the archetype of the classic dress watch, and the 31 mm mid-size configuration represented by reference 178240WRO sits at the heart of that legacy. Introduced in 1945 as the first self-winding wristwatch to display the date in a window on the dial, the Datejust established a design language so coherent and enduring that its silhouette remains essentially unchanged to this day. The 31 mm case size emerged to serve wearers who wanted a watch that reads as distinctly Rolex without leaning into the larger, sportier proportions of the 36 mm or 41 mm references, and it has earned a devoted following among both women and men who prefer a refined, mid-size presence on the wrist.

The case and bracelet of the 178240WRO are crafted entirely in Oystersteel, Rolex's proprietary 904L stainless steel alloy, which is chosen for its exceptional resistance to corrosion and its ability to take and hold a brilliant polish. The 31 mm Oyster case is a technical achievement in its own right—a hermetically sealed three-piece construction that protects the movement from water to 100 meters (330 feet), making it genuinely capable of accompanying an active lifestyle without sacrificing elegance. The smooth domed bezel crowns the case with a pure, uninterrupted arc of steel, forgoing the fluted or diamond-set options in favor of an understated architectural line that keeps the eye moving to the dial.

The dial is where the 178240WRO makes its most memorable impression. A white lacquer ground provides a luminous, porcelain-like backdrop that maximizes legibility, while applied Roman numerals rendered in polished metal add a classical typographic character that connects this watch to centuries of horological tradition. The Roman numeral layout is particularly well-suited to the 31 mm proportions, lending each hour marker a deliberate presence that reads as confidently luxurious at a glance. The date aperture at 3 o'clock, framed by the signature Cyclops magnification lens on the crystal, completes the functional signature that has defined every Datejust since the very first reference.

Power comes from a Rolex automatic movement, a self-winding caliber that winds through the motion of the wearer's wrist via a bidirectional rotor. Rolex automatic movements in this reference class are built to COSC-certified chronometer standards, ensuring daily accuracy that far exceeds industry expectations. The movement is serviced and regulated in-house by Rolex to tolerances tighter than the official chronometer specification, and its architecture is engineered for long service intervals, making the 178240WRO as practical as it is beautiful.

On the wrist, the 31 mm Datejust projects quiet authority. The Oyster bracelet—with its characteristic three-link flat design—hugs the wrist securely and articulates smoothly, and its mix of brushed center links and polished outer links mirrors the case finishing to create a unified, jewelry-quality silhouette. Whether worn with a tailored suit, a casual weekend ensemble, or an elegant evening outfit, this watch transitions effortlessly, which is perhaps the most defining virtue of the Datejust family across its entire history.

At Bizak and Co., we specialize in sourcing and presenting pre-owned and unworn Rolex references to discerning buyers across the United States. The Datejust 31 reference 178240WRO in white Roman dial configuration is a perennially sought-after piece, appreciated for its balance of wearability, heritage, and investment stability. Please note that Bizak and Co. is not an authorized Rolex dealer; all watches are sold on the secondary market. We encourage you to contact us directly for current availability, condition details, and pricing—our team is ready to help you acquire this iconic reference with confidence.