Strap for Datejust 31 Stainless Steel Domed / Oyster / Blue

The Rolex Datejust 31 ref. 178240-0023 has a lug width of 16mm. This measurement is taken with a digital calliper positioned between the lower lugs, flush against the caseback. It is specific to the 31mm variant and should not be confused with the 20mm of the Datejust 36 or the 13mm of the Lady-Datejust 26.

For a steel Datejust 31, an alligator strap in vegetable-tanned leather — either belly or hornback — is the most coherent choice given the dress-watch character of the piece. Box-calf leather is the sartorial alternative, developing a refined patina over time. For everyday mixed use, a 1.2mm technical nylon NATO or a vulcanised rubber strap offer practicality without compromising the overall aesthetic.

The strap is removed using a spring bar tool: insert the forked tip into the lug slot, compress the spring bar, and slide the strap free. Work on a soft cloth to protect the polished steel case. Refit by seating one end of the spring bar into the lug first, then compressing the opposite side until it clicks into place. Care should be taken not to scratch the case or lugs during the operation.

Yes. The 16mm lug width is fully covered by milanostraps.it's handcrafted range, including alligator, calf leather, shell cordovan, NATO and rubber straps. All models are cut to the exact 16mm specification with no adapters required. Straps are available to order online in the 16mm section, or as bespoke commissions through the Casati Milano atelier.

Longevity depends on the material and frequency of use. A vegetable-tanned alligator strap, properly maintained — rotated with other straps, kept dry, and occasionally treated with neutral leather cream — will retain its structural and aesthetic integrity for 3 to 5 years of regular wear. Box-calf has a similar lifespan but develops patina more quickly. Shell cordovan is the most durable option: its dense fibrous structure resists wear better than any other equine or bovine leather.