Strap for Seamaster 120M Automatic 36.25 Yellow Gold / White

The lug width of the Seamaster 120M ref. 2101.21.00 is 18 mm. This measurement is specific to this model and does not correspond to more common standards (16 mm, 20 mm). To verify it, measure with a caliper the internal diameter of the lugs where the strap rests: it must be exactly 18 mm. It is crucial not to confuse this measurement with Seamaster watches from other series, which may have different lugs.

For a Seamaster 120M ref. 2101.21.00 in yellow gold, the most suitable materials are brown alligator (natural color pairing), vegetable-tanned calf leather (which develops a patina similar to gold over time), and shell cordovan (for superior elasticity and extended comfort). Dark brown alligator pairs perfectly with the amber tone of Seventies gold. We advise against synthetic nylon and inexpensive canvas: they do not match the constructive dignity of a gold watch.

The procedure requires care. Obtain a spring bar tool with a double tip, one for each side. Position the watch on a soft surface (felt cloth). Insert the tip of the tool into the slot next to the lug, applying gentle pressure to release the retaining spring. Never force. Once both springs are extracted, the strap comes off. To reattach, align the two springs on the new strap and snap them into the lug slots with precision. If unsure, consult a professional watchmaker.

Yes, provided that the strap is constructed for an 18 mm lug width. Most standard aftermarket straps (16 mm, 20 mm) are not compatible. Some artisanal manufacturers, such as those available on Milano Straps, produce custom straps specifically for this lug width. Always verify the technical specifications and consult the seller before purchase to avoid incompatibility.

Durability depends on the material and intensity of use. A quality artisanal alligator strap lasts 3-5 years with daily wear, vegetable-tanned calf develops aesthetic patina and lasts 2-4 years, shell cordovan can exceed 5-7 years thanks to superior elastic properties. Constant exposure to sweat, moisture and sun accelerates aging. Regular maintenance (gentle cleaning, immediate drying after water contact) significantly extends the strap's life. Standard artisanal warranty is 18 months.