Strap for Datejust 31 Yellow Gold Diamond / President / Black Diamond

The lug width is 16 millimetres. This measurement represents the internal distance between the strap attachment pins on the case. It is specific to the Datejust 31 reference 178158-0011 and is not interchangeable with adjacent sizes such as 14mm or 18mm. You can verify it by removing the current strap and measuring the distance between the two horizontal pins.

Alligator in cognac or brown tones is the classic choice, as it enhances the warmth of the gold without visual competition. Alternatively, Hermès calf or equivalent leathers guarantee refined finishing and a patina that develops over time. For those preferring sustainability, high-quality vegetable tanning offers authenticity and visible patination. We advise against NATO or rubber, which would tend to diminish the formal and sartorial character of the watch.

The procedure requires a spring bar tool (a specialized watchmaker's screwdriver). First remove one side of the strap by gently inserting the tool into the hole beneath the pin, releasing the small internal spring. Repeat on the other side. Then insert the new strap, ensuring the pins seat firmly in their positions. If you are inexperienced, we recommend entrusting the operation to a specialist watchmaker to avoid scratching the case.

Yes, provided that the lug width is exactly 16 millimetres. High-quality artisanal straps, such as those created by Casati Milano, are perfectly compatible. Ensure that the pins are positioned correctly and that the strap width is not excessive relative to the case dimensions (thicknesses exceeding 3–4 millimetres in the attachment section are not recommended).

Durability depends on the material, usage and maintenance. A quality artisanal alligator or shell cordovan strap can last 3–5 years with daily wear and appropriate care (avoid salt water, aggressive detergents, and dry after perspiration). Calf leather typically lasts 2–3 years. All straps benefit from gentle brushing with soft brushes and periodic rest to avoid constant stress. Casati Milano offers an 18-month warranty against manufacturing defects.