Strap for Seamaster Master Co-Axial 39.5 New York Edition Stainless Steel / Grey / Alligator

The lug width of the Seamaster 511.13.40.20.02.002 is 20 millimeters. This dimension corresponds to the width of the flanges between the spring bar lugs of the case. To verify it, measure the internal distance between the two metal eyelets where the watch strap pins are inserted. It is essential to identify this measurement correctly before purchasing an aftermarket strap.

For the Seamaster City Edition New York we recommend three options according to intended use: burgundy or brown alligator for formal elegance, shell cordovan for those desiring a patina that ages naturally over time, and vegetable-tanned calf for the compromise between sustainability and longevity. For sports purposes, NATO nylon or rubber strap preserve the technical DNA of the model.

The strap is replaced by removing the spring bars that connect the lugs to the case. Using a dedicated tool (spring bar tool), gently press the pin to compress the internal spring, extract the pin, then slide off the old strap. Insert the new strap into the lug hole and reinstall the pin ensuring it is fully seated. If you prefer to avoid the risk, entrust the work to our Casati Milano atelier.

Yes, any strap with 20mm lug width is compatible with the Seamaster 511.13.40.20.02.002, provided that the thickness of the leather or material does not obstruct mounting to the lugs. Our straps on milanostraps.it are tested for this compatibility. For particular configurations, the Casati Milano atelier creates custom straps.

The longevity of a leather strap depends on usage intensity, climate, and material. A quality alligator or shell cordovan, with moderate daily use, maintains structural integrity for 3-5 years. Vegetable-tanned calf, slightly more vulnerable to moisture, typically lasts 2-4 years. All our handcrafted straps are guaranteed for 18 months and can be regenerated at Casati Milano through selective repair.