Strap for Seamaster Aqua Terra 150M Master Co-Axial 38.5 Stainless Steel / Red Gold / MOP / Bracelet

The lug width of the 231.20.39.21.55.003 model is 20 mm. This means that any compatible strap must have an internal width between the spring bars of exactly 20 mm. You can verify this by measuring with a digital caliper the distance between the two metal pins of the case.

To enhance the elegance of the two-tone 231.20.39.21.55.003, we recommend an alligator strap with vegetable tanning in shades of brown, cognac, or dark grey. Alligator offers a sophisticated texture that does not compete with the mother-of-pearl dial, while vegetable tanning develops a natural patina over time, synchronizing with the aging of the case. Alternatively, grey-smoke regenerated calf leather for a more contemporary style.

Strap replacement requires a precision tool called a spring bar tool. Position the watch on a soft and stable surface. Insert the curved tip of the tool under the metal spring bar, gently pushing toward the center of the case to compress the internal spring. The pin will release and the old strap can be removed. Repeat on the other side. To install the new strap, align the holes at the ends of the new strap with the spring bars, then insert the pin compressing it slightly until it clicks into place.

Yes, the 20 mm strap of the 231.20.39.21.55.003 is compatible with other Omega watches that mount the same lug width, such as certain Seamaster and Explorer models. However, the aesthetic proportions of the case and the specific design of the mother-of-pearl dial may require case-by-case evaluations. We always recommend verifying the technical specifications of the destination model before transferring the strap.

A quality vegetable-tanned leather strap, with proper maintenance, typically lasts 2-4 years before requiring replacement. Durability depends on frequency of use, exposure to humidity, and type of tanning. Casati Milano straps benefit from an 18-month warranty and are made with premium leathers selected for resistance and aesthetic beauty. To extend the life of your strap, avoid prolonged immersion and allow the leather to dry completely after exposure to moisture.