Strap for Constellation Co-Axial 31 White Gold / Diamond / Black Supernova

The lug width is 18mm. This is a precise structural requirement: a compatible strap must measure exactly 18.00mm ±0.2mm in width at the attachment point. Measure with a digital caliper positioned perpendicularly between the two lugs of the case to verify compatibility.

It depends on usage. Alligator is the most sophisticated and elegant choice; vegetable-tanned calf offers natural patina and aesthetic aging; shell cordovan combines structure and suppleness; rubber guarantees modern functionality; NATO remains versatile for casual contexts. We recommend matching the color to the cool tone of white gold: navy blue, taupe brown, deep black, or light grey.

Use a spring bar tool to gently compress the spring bar (the small metal spring inside the lug). Position the tool in the spring bar groove, push toward the center of the case to release tension, and remove the lug. Repeat on the opposite side. Insert the new strap by reversing the process. Avoid forcing: a damaged spring bar is difficult to replace and compromises strap retention.

No. Aftermarket straps must be specifically manufactured for 18mm lugs. Straps for 20mm or 16mm lugs will not fit properly and risk damaging the case lugs. On Milano Straps you will find a selection of certified 18mm straps, customizable and guaranteed for 18 months.

Duration varies depending on material and daily use. A vegetable-tanned calf, with regular maintenance (light cleaning, protection from moisture), lasts 3–5 years before replacement is needed. Alligator and shell cordovan are more durable and can last 5–7 years. Rubber lasts 4–6 years. Contact Casati Milano for advice on leather maintenance and regeneration.