Rolex
Datejust 31 278381rbr-0004— lug 16mm

The Rolex Datejust 31 reference 278381rbr-0004 has a lug width of 16mm. This is the standard distance between the lugs on the case, determined by Rolex to maintain perfect optical proportions with the 31mm diameter. A 16mm strap fits precisely into the lugs without forcing and ensures structural security of the watch.

For the Datejust 31 278381rbr-0004 in Rolesor (steel and rose gold), we recommend superior alligator for controlled contrast with the case, or vegetable-tanned calf for a patina that evolves with age. Shell cordovan is the rare and extraordinary choice: maximum density, natural lustre that mirrors the Rolesor, unmatched durability. For casual wear, woven nylon NATO allows an informal reinterpretation whilst maintaining elegance.

Changing the strap requires a dedicated tool (spring bar tool) to remove the lugs from the case. This is not recommended for inexperienced users; Casati Milano provides the strap replacement service at the atelier by appointment, with personalised WhatsApp follow-up and an 18-month warranty on the new craftsmanship.

Any 16mm strap with standard lugs is compatible with the Datejust 31 reference 278381rbr-0004. Ensure the lugs accept removable spring bars and that the width is precisely 16mm. Milanostraps.it offers a collection of handcrafted 16mm straps, selected for optical proportions and construction quality suitable for Rolesor.

A high-quality leather strap (alligator, shell cordovan, vegetable-tanned calf) lasts 3–5 years with responsible daily wear. Longevity depends on frequency of use, ambient humidity, and maintenance. Vegetable-tanned calf ages with character and can last 7–10 years with moderate care (occasional cleaning, protection from heavy rain). The original Rolex strap typically lasts 3–4 years.