Strap for Constellation Master Chronometer 39 Stainless Steel / Sedna / Brown / Alligator

Your Constellation 131.23.39.20.13.001 has a lug width of 24 millimetres. This measurement is essential for choosing a compatible strap. To verify it correctly, measure the internal distance between the two lugs (the strap attachments) with a digital calliper: it should be exactly 24mm. If the strap does not respect this measurement, it will not attach correctly and you risk damaging both the case and the strap itself.

For the Constellation 131.23.39.20.13.001 we recommend an alligator in vegetable tanning in dark brown or a burgundy shell cordovan. Alligator develops a natural patina over time, creating that feeling of an authentically worn watch. Shell cordovan instead offers a uniform surface and an incredibly compact structure, perfect for enhancing the nobility of Sedna Gold. Both materials age beautifully and integrate visually with the formal character of the watch.

To change the strap on your Constellation 131.23.39.20.13.001, you will need a spring bar tool (a specific tool with two curved ends) and great delicacy. Position the end of the tool under the release spring, press towards the centre of the case and the strap will detach easily. Once removed, repeat the procedure on the other side. To install the new 24mm strap, insert the release spring into the lug holes and press until you feel the "click" that confirms a secure attachment. If you prefer to avoid the risk, the Casati Milano atelier performs strap changes free of charge with the purchase of an artisanal strap.

Yes, any 24 millimetre strap will be compatible with your Constellation 131.23.39.20.13.001, provided it respects exactly the lug width. On Milano Straps you will find a selection of 24mm straps in alligator, shell cordovan, vegetable calf and FKM rubber, all tested to guarantee a perfect fit. Each strap is supplied already cut to standard length, but can be customised in length, initials and stitching thread colour. Before ordering, always verify that the strap indicated is specified for 24mm.

The lifespan of a leather strap depends on the material, use and maintenance. A quality artisanal alligator or shell cordovan, such as those supplied by Milano Straps, can last 3 to 5 years with regular use, developing a prized patina. A superior quality vegetable calf usually lasts 2-4 years. The Casati Milano atelier guarantees 18 months on every artisanal strap produced, during which time it corrects or replaces free of charge any defects in workmanship. To extend the lifespan, we recommend avoiding direct exposure to sun and water, and applying a protective balm every 4-6 months.