Strap for Seamaster Master Co-Axial 39.5 Edizione Venezia Sedna Gold / Silver / Alligator

The lug width of the Seamaster 511.53.40.20.02.001 is 20mm. This measurement represents the distance between the two spring bars of the case and is essential for selecting a compatible strap. If you wish to verify it personally, use a digital caliper by measuring the internal space between the spring bars: a common mistake is including the outer edges of the case, which would distort the measurement.

For the Seamaster 511.53.40.20.02.001 in Sedna Gold we recommend two directions: an alligator or crocodile leather with vegetable tanning (cognac-brown or navy blue colour) that complements the copper tone of the case and develops a natural patina over time; or a whiskey or bordeaux shell cordovan for those seeking dense and durable leather. High-quality calf leather (Hermès Swift or Chèvre) offers superior comfort if worn regularly. For marine environments, a NATO textilene or fluoroelastomer rubber ensures waterproofing and practicality.

The procedure is straightforward: place the watch on a soft surface (to protect the caseback), locate the spring bars on the sides of the case and, using a dedicated tool (spring bar tool) or a small flat-head screwdriver, press the bar to release the internal spring. The old strap will slip out easily. Insert the new strap by aligning the holes at the ends with the spring bars, and push upward until the bar clicks back into position. If you prefer to avoid the risk of scratching the case, contact Casati Milano atelier for a professional replacement.

All straps with a 20mm lug width are physically compatible with this model. The choice depends on style: Italian artisanal leathers (alligator, calf, cordovan) with a deployant buckle for a formal look; NATO or rubber straps for sportswear and wet environments; interwoven nylon straps for urban casual. On MilanoStraps you will find a selection of 20mm straps, many customizable in colour, initials and stitch thickness.

Longevity depends on the material and usage conditions. High-quality alligator or calf leather, worn 4-5 days a week in normal conditions (not wet), lasts 3-5 years before showing signs of wear on the stitching. Shell cordovan, thanks to its superior density, reaches 7-10 years. Vegetable-tanned leathers tend to age more rapidly if exposed to moisture and rain, but acquire a fascinating patina. A fluoroelastomer rubber lasts almost indefinitely in terms of structural resistance, although the colour may fade over time. Casati Milano provides an 18-month warranty on all straps, with the possibility of repair.