Strap for Seamaster 120M Automatic 36.25 Yellow Gold / Blue

The Omega Seamaster 120M reference 2101.81.00 requires straps with a lug width of 18mm, which corresponds to the distance between the inner shoulders of the case. It is not a standard measurement: it is intermediate between the 16mm of compact chronographs and the 20mm widespread in modern sports collections. The lug geometry is parallel, without compensative angles.

For the Seamaster 120M 2101.81.00 in yellow gold, alligator represents the most appropriate formal choice: the natural grain dialogues with the warmth of the precious metal. Recommended shades: honey, caramel, bordeaux. Alternatively, vegetable-tanned calf develops a patina that ages in harmony with the gold's oxidation. Shell cordovan creates a heritage aesthetic thanks to its density and luminous reflection.

Position a ruler horizontally on the watch case, measuring the distance between the two internal attachment points (the shoulders). For the 2101.81.00, the result must be exactly 18mm. Avoid measuring the old strap, which may be worn or stretched. If the strap has an angle, measure nonetheless the point where it enters the case: that is the true lug width.

A leather strap of artisanal quality on a Seamaster 120M has a lifespan of 4-7 years with daily use, variable according to the material. Alligator and shell cordovan age more gradually and develop a desirable patina. Vegetable-tanned calf can last 5-8 years thanks to the dense fiber. Wear always begins in the inner loops and along the strap fold. Casati Milano warranty covers 18 months against manufacturing defects and material flaws.

Yes, both NATO and rubber are compatible with the 18mm lug width. A NATO in heavy canvas keeps the Seamaster in its narrative sports-professional context; rubber, in neutral tones (gray, black, blue), creates a paradoxical and fascinating contrast on yellow gold, celebrating the absurdity of wearing a diving chronometer in civil contexts. Both combinations require a conscious aesthetic choice, not automatic practicality.