Strap for Seamaster Aqua Terra 150M Co-Axial 39.2 Yellow Gold / Black

The lug width of reference 2603.50.37 is 18mm. This measurement corresponds to the internal distance between the two lateral protrusions of the case where the strap is inserted. Measuring the lug width correctly is essential to ensure an ergonomic fit without gaps or unwanted pressure.

For a timepiece in 18-carat yellow gold such as the 2603.50.37, we recommend an alligator in vegetable tanning in Cognac or dark brown tone, which amplifies the chromatic richness of the gold and develops a natural patina over time. Alternatively, white-cream English calf offers modernity and contrast, while bordeaux shell cordovan creates an unmatched visual depth among formal leathers.

The Aqua Terra 2603.50.37 uses a standard spring bar system with bars removed laterally. Position the watch on a soft pad, locate the small recesses under the lugs, insert a dedicated tool (spring bar tool) to compress the inner bar, then remove the old strap. Insert the bar into the new strap and secure it again to the lugs. If you prefer to avoid any risk, the Casati Milano atelier offers strap replacement service with warranty at no additional cost.

Yes, any strap with 18mm lug width is physically compatible with the 2603.50.37. However, to fully enhance the yellow gold case and guilloché dial, we recommend artisanal straps of superior quality in noble leathers such as alligator, premium calf or shell cordovan, custom-made at certified ateliers.

The lifespan depends on the material and usage. Vegetable-tanned alligator can last 5-7 years with appropriate maintenance (water protection, annual conditioning). Shell cordovan, thanks to its intrinsic density, easily reaches 8-10 years. Standard calf offers 3-4 years. These timeframes increase significantly if the strap is custom-made and does not undergo concentrated stress on the buckle.