Strap for Constellation Master Chronometer 39 Stainless Steel / Silver / Bracelet

The lug width of the 131.10.39.20.06.001 is 24 millimeters. This measurement is critical to ensure compatibility with aftermarket straps. To verify it correctly, measure the distance between the two terminals of the spring bar using a digital caliper, or examine the width of the space where the strap sits on the case. All 24mm straps from Milano Straps are suitable for this model.

The choice depends on intended use. For formal occasions and business contexts, we recommend black alligator with white silk stitching: the natural texture of crocodile leather enhances the watch's prestige without competing visually with the silver dial. For daily wear, medium brown shell cordovan develops a natural patina over time, creating an emotional connection with the watch. Vegetable-tanned calf leather offers the best aesthetic-sustainability compromise. For daytime versatility, structured FKM rubber allows elegant transitions without sacrificing functionality.

The procedure requires precise tools to avoid case damage. Locate the strap lug pins (the current strap is either glued or held by small spring mechanisms). Use a specific tool (spring bar tool) to compress the strap spring bar inward, allowing you to extract the pin from the terminal. Once extracted, the strap comes off. Repeat the operation on the other side. To install the new strap, align the two terminal holes with the pins, compress the spring again, and insert the pin. Ensure the strap is symmetrical and properly seated. If you lack the tools or prefer to avoid risk, the Casati Milano atelier offers a strap change service with warranty.

Absolutely yes. A quality certified artisanal strap, built with the same metronomic precision as the watch itself, will not damage the case. Compatibility is guaranteed by the standardized 24 millimeter lug width. However, we recommend verifying two aspects: the strap must not have sharp edges that could scratch the case (a good craftsman smooths the edges), and the length of the lugs must allow stable seating in the terminals without excessive play. The 24mm straps from Milano Straps and the Casati Milan atelier meet these precision standards.

Durability depends on material and intensity of use. Shell cordovan with vegetable tanning, subjected to moderate daily wear, maintains functionality and aesthetics for 5-7 years before replacement is needed. Alligator, especially with specific protective finishes, reaches 7-10 years. Vegetable-tanned calf is more vulnerable to environmental factors, so count on 4-6 years. Exposure to humidity, perspiration, and temperature variations accelerate the natural degradation of leather. The good news: unlike metal bracelets, a leather strap is easy and economical to replace. Casati Milano offers an 18-month warranty on every custom strap, covering manufacturing defects and ensuring controlled durability from the start.