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

The Omega Seamaster 120M reference 2105.21.00 features an 18 mm lug width, measured center-to-center of the attachment lugs. This standard is critical when purchasing compatible straps: undersized straps (16 mm) will not fit into the lugs, while oversized straps (20 mm) will create aesthetic instability. Always measure with precision using a digital caliper positioned perpendicularly to the lugs.

For the Seamaster 120M 2105.21.00 in yellow gold, vegetable-tanned alligator represents the most sophisticated choice: the natural grain dialogue with the case's smoothness without material excess. Burgundy or dark brown calf offers tactile fluidity, while shell cordovan creates an inner luminosity that the gold reflects masterfully. NATO rubber-textile remains valid for those desiring reversibility and sportive ease in everyday wear.

Changing the strap on the Seamaster 120M 2105.21.00 requires: (1) position the watch case-side up, (2) locate the spring bars (small pins that traverse the lugs), (3) use a spring bar tool for controlled pin depression, sliding it laterally until the lug disengages, (4) remove the old strap, (5) position the new strap aligning the holes to the lugs, (6) reinsert the pin with firm pressure until retention clicks. If unsure, contact Casati Milano for technical support.

Any quality artisanal strap constructed for the 18 mm lug width is compatible with the Seamaster 120M 2105.21.00. On milanostraps.it you'll find a selection of <a href="https://milanostraps.it/collections/cinturini-orologi-per-misura-ansa-18mm">18mm straps</a> in alligator, calf, shell cordovan and textile, available in multiple color configurations and customizations. The Casati Milano atelier also creates bespoke straps with direct leather selection and finishes.

The lifespan of a natural leather strap varies according to material, climate, and use. Alligator with vegetable tanning, subject to moderate humidity and periodic treatment with natural creams, tends to develop distinguished patina while remaining functional for 5-8 years. Vegetable-tanned calf offers 4-6 years under optimal conditions. Shell cordovan, the most resistant natural leather, exceeds 10 years. Rubber-textile remains stable indefinitely. Casati Milano atelier offers an 18-month warranty on all straps and accepts revisions and restorations over the years.