Strap for Speedmaster Reduced Ladies Stainless Steel / Diamond / Blue MOP

The lug width of the 3815.73.31 is 18 mm. This dimension is fixed and allows compatibility with all artisanal straps designed for 18 mm lugs. To verify compatibility, position a caliper between the two spring bar attachments of the strap at the case: the correct distance is exactly 18 mm.

It depends on your personal style and intended use. For formal elegance, brown or black alligator is unsurpassed. If you seek versatility and natural patina evolving over time, vegetable-tanned calf leather offers the best balance between aesthetics and longevity. For extreme durability, horse shell cordovan is practically indestructible and develops a fascinating patina. For sporty-vintage character, ballistic canvas with deployant clasp is the authentic choice.

Position the watch on a flat surface. Locate the strap lugs: these are the two lateral extensions that hold the spring bar attachments. Using a dedicated tool (spring bar tool) or a thin blade, gently push one of the spring bars toward the center of the case to release the lug. Repeat on the other side. Remove the old strap and insert the new one, ensuring the spring bars are fully inserted into the lugs and do not protrude beyond the ends.

Yes, absolutely. The 3815.73.31 is fitted with standard 18 mm lugs, which means any quality artisanal strap with the same lug width is compatible. Simply verify that the strap is not too thick: a 3-4 mm thickness adapts perfectly to the lugs without creating slack or friction. Straps in alligator, calf, shell cordovan, ballistic canvas and specialized rubber are all valid options.

Durability depends on the material and usage. A quality artisanal alligator or calf strap lasts an average of 3-5 years with daily wear, developing authentic patina in the process. Shell cordovan is practically indestructible and easily surpasses 10 years. Specialized rubber straps maintain performance for 2-3 years before requiring replacement. To extend lifespan, avoid prolonged exposure to direct moisture and intense sunlight, and occasionally apply a leather conditioner to leather straps.