Strap for Seamaster Master Co-Axial 39.5 Olympic Timekeeper Stainless Steel / White / Yellow

The lug width of the Seamaster Aqua Terra 39.50mm is precisely 20mm. This dimension is specific to this model and does not correspond to universal standards. Be sure to manually verify the distance between the spring bar mounting holes before purchasing an aftermarket strap to avoid fit incompatibility.

Alligator in blue or black tones is the ideal choice for this model's blue sunburst dial: the natural grain of the leather creates aesthetic harmony without competing visually. Alternatively, vegetable-tanned calf offers softness and versatility, developing a rich patina over time. For intensive marine use, a NATO strap in Ballistic canvas guarantees water resistance and quick changes.

Obtain a spring bar tool (available from specialized retailers). Gently unscrew one of the spring bars positioned in the case lugs, leveraging the small mounting slot. Remove the spring bar, then slide out the old strap. Align the new strap and reinsert the spring bar with controlled pressure until you hear the locking click. Verify the fastening by gently pulling the strap.

Yes. Milanostraps.it offers artisanal alligator, calf and NATO straps specifically sized for the 20mm lug width of this model. All straps are customizable in fit, initials and stitching thread. For a complete bespoke service, the Casati Milano atelier creates made-to-measure straps with leather selection and 18-month warranty.

An artisanal quality alligator or calf strap, worn daily under normal conditions, maintains structural integrity for 3-5 years. Longevity depends on sun exposure, humidity, frequency of wear and maintenance care. Vegetable-tanned leather, thanks to natural tannins, develops a protective patina that can extend useful life. Casati Milano offers an 18-month warranty and repair services by appointment.