Strap for Divers Sixty-Five 40 Chronograph Stainless Steel / Black / Bracelet

The lug width is precisely 21 mm. This dimension is exclusive to this model and requires straps specifically constructed to this exact geometry. To verify compatibility, measure the distance between the two lugs at the attachment holes.

Selection depends on intended use. For discrete elegance: vegetable-tanned calf or polished alligator. For aquatic practicality: haute couture nylon NATO or FKM rubber. The tonneau case harmonises beautifully with rich brown leather, whilst the sunburst dial stands out against dark red or black NATO.

Remove the watch from your wrist. Use a spring bar tool to apply pressure to each end of the internal spring that secures the lug. Once released, extract the worn strap and insert the new one, aligning it with the attachment holes. Ensure the spring is properly seated before closing. Do not force: the mechanism must click distinctly.

No, a 21 mm strap is constructed exclusively for this lug width. Other Oris sports models (Aquis, Vintage, Regulator) employ 20 or 22 mm lugs. Always verify the measurement before purchase to avoid returns. MilanoStraps specifically catalogues 21 mm-compatible models.

With moderate use and regular cleaning (distilled water, neutral soap), vegetable-tanned leather lasts 3–5 years. Frequent freshwater exposure accelerates ageing; chlorine drastically reduces longevity. FKM rubber resists 5–7 years under identical conditions. Patina development is not degradation: it is material ennobling.