Rolex
Datejust 31 278288rbr-0026— lug 16mm

The lug width of the Rolex Datejust 31 278288rbr-0026 is 16 millimetres. This measurement represents the internal distance between the two lugs where the strap is anchored to the case. A 16mm lug width is specific to this model and is not compatible with straps designed for other widths. Measurement should be taken with a caliper inserted perpendicularly between the lugs to ensure accuracy and proper strap selection.

For the yellow gold Datejust 31, alligator leather in vegetable tanning remains the most aesthetically coherent choice. The natural grain of alligator amplifies the luminosity of yellow gold, creating a sophisticated tactile and visual dialogue. Alternatively, quality calf leather with drum-tanned finish develops a soft natural patina that accompanies the ageing of gold over time. For formal contexts, shell cordovan offers chromatic density and colour stability. All these materials, available in 16mm versions from milanostraps.it, allow harmonious proportion with the 31mm case.

Strap replacement on a Rolex Datejust 31 is achieved via the spring bars that secure the strap to the case lugs. A spring bar tool—a small bifurcated instrument—is used to release the spring and slide out the old strap. Once removed, the new strap is positioned aligned with the lug ends and the spring is allowed to fall back into its housing. This procedure is identical for any 16mm strap. If inexperienced, the Casati Milano team is available for assistance in their Milan atelier.

Yes, it is absolutely possible to use an aftermarket strap on this case, provided it has a 16-millimetre lug width. Quality artisanal straps, such as those available from milanostraps.it, often offer superior finishing and aesthetic customisation that Rolex originals do not permit. An aftermarket strap in fine leather—alligator, calf, shell cordovan—does not affect the watch's functionality and allows greater creative freedom in colour pairing and texture selection.

A quality natural leather strap, made with vegetable tanning and superior hide, has an average lifespan of 3–5 years of regular wear (3–4 days per week). This estimate depends on frequency of use, exposure to moisture, sun and perspiration, and daily care. An alligator or shell cordovan strap tends to last longer than standard calf due to superior material density. The 18-month guarantee on manufacturing defects offered by Casati Milano covers potential construction flaws; natural leather ageing remains a physiological biological process.