Strap for Seamaster 120M Automatic 36.25 Yellow Gold / Diamond / Champagne

The lug width of the Seamaster 120M 2105.10.00 is exactly 18mm. This measurement corresponds to the distance between the spring bar pins (the axes that support the strap on the case). It is a fixed parameter for this reference and fundamental for selecting compatible aftermarket straps.

Alligator in cognac or dark brown tones is the most natural choice to enhance the yellow gold without competing visually. Alternatively, vegetable-tanned calf leather allows for a natural patina over time. For sport use, a thick canvas NATO in grey or navy blue reinvents the piece in casual diving register.

The change requires a specific tool (spring bar tool) to remove the spring bar pins. Position the tool in the lateral grooves of the pins, press gently downward and extract the pin from the case. Repeat on the other lug. To avoid scratches, entrust the operation to a watchmaker or use a bench vise with rubber protection.

Yes. Many specialized manufacturers offer straps in 18mm size, in both leather (alligator, calf, shell cordovan) and technical materials (NATO, FKM rubber). Always verify that the lug width is exactly 18mm to avoid play or excessive tension on the case.

A quality alligator strap can last 4-6 years of regular use, up to 10 years if alternated with other straps. Vegetable-tanned calf leather has similar durability but develops a visible patina more quickly. Wear depends on sun exposure, humidity, perspiration and frequency of wear.