Strap for Master Collection 40mm Annual Calendar Stainless Steel / Silver-Diamond / Bracelet

The lug width of the Longines Master Collection L2.910.4.77.6 is precisely 21 millimetres. This measurement is taken between the lug pins and is critical for purchasing a compatible strap. Always verify this dimension using a digital calliper to avoid acquiring adjacent widths (20mm or 22mm), which will not seat correctly in the case's passants.

For this watch's aesthetic, a cognac brown alligator strap or vegetable-tanned calf leather in honey tone is recommended. These materials dialogue elegantly with the satinised stainless steel case without competing visually. For a sporty interpretation, a grey charcoal NATO in cordura fabric maintains the classical sobriety of the design.

Strap replacement requires two tools: a spring bar tool and a small plastic or steel lever. Position the watch with the lug facing you, insert the tool into the lateral groove of the spring bar to compress the internal retainer, and pull gently downward. The strap will detach. To install the new strap, compress the spring bar into the new seat and ensure the retainer clicks firmly into position.

Yes, the L2.910.4.77.6 is fully compatible with aftermarket straps of 21mm width. It is essential to verify that the width is precise and that the strap is constructed from premium materials (high-quality leather, suitable rubber, or textile) to preserve the watch's aesthetic elegance. Milanostraps offers fully personalizable compatible straps.

A high-quality strap with vegetable tanning and artisanal construction typically lasts 3–5 years with moderate daily wear. Longevity depends on environmental humidity, frequency of use, and care (periodic cleaning, drying if wet, avoiding prolonged sun exposure). The patina that develops over time is part of the leather's natural aesthetic, not a defect. Casati Milano guarantees 18 months on craftsmanship.