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

The lug width of the Omega Aqua Terra 231.25.39.21.55.001 is 20mm. This width is measured between the spring bars (pins) that attach the strap to the case. It is the fundamental technical specification for ensuring compatibility with aftermarket straps. You can verify it by placing a measuring tape horizontally between the two pins, from the inner edge to the other inner edge.

For this model with an opalescent mother-of-pearl dial and red gold-steel bicolor case, we recommend alligator dyed in deep navy (midnight) for chromatic resonance with the dial, or vegetable-tanned calf leather in whiskey/cognac tones that complement the rose gold. Formal black (alligator or calf) offers universal elegance and sober contrast. For dynamic use, a canvas NATO or natural white calf leather add versatility.

The strap on the Aqua Terra 231.25.39.21.55.001 is secured by spring bars (small horizontal metal springs at the lug level). Using a spring bar tool (dedicated tool), gently press inward one of the two pins to release it, then pull out the strap end. Repeat on the other side. To mount the new strap, insert the ends of the new strap into the case slots, then push the pins inward with the spring bar tool until they are correctly positioned. Ensure both pins are firmly seated before wearing the watch.

Yes, it is fully compatible with aftermarket straps in 20mm lug width. The Aqua Terra case, although originally supplied with an integrated bracelet, allows strap replacement via standard spring bars. Our <a href="https://milanostraps.it/collections/cinturini-orologi-per-misura-ansa-20mm">20mm straps</a> are designed and tested for this model, ensuring secure attachment and aesthetically consistent proportions.

The lifespan of a leather strap depends on frequency of use and moisture exposure. A strap in alligator or calf leather, on a daily wear watch like the Aqua Terra, typically lasts from 3 to 5 years. Vegetable-tanned leather develops a patina that improves over time, but the strap naturally tends to lose elasticity and weaken at the shoulders. Our artisanal straps are guaranteed for 18 months, with the option for maintenance and replacement at Casati Milano.