Strap for Master Collection 40mm Annual Calendar Stainless Steel / Blue / Bracelet

The lug width of the Longines Master Collection L2.910.4.92.6 is 21mm. This precise measurement is determined by the case geometry and the proportions of the dial. To verify strap compatibility, measure the distance between the lugs using a digital calliper or consult the official Longines documentation provided with your watch. The strap must fit perfectly to the lugs without gaps or twisting.

The ideal material depends on your intended use and aesthetic preferences. For formal occasions and ceremonies, alligator leather with vegetable tanning enhances the classical character of the Master Collection through its natural texture and the patina it develops over time. Tuscan calf is versatile and suited to semi-formal contexts, maintaining the geometric rigour of the timepiece. Japanese shell cordovan combines robustness, sophisticated aesthetics and mechanical durability. For casual, sporty applications, black or charcoal-grey rubber straps offer practicality and superior water resistance.

The Master Collection L2.910.4.92.6 strap is changed by removing the spring bars (lug pins) that connect the strap to the case. Use a dedicated tool—a spring bar tool—to gently compress the internal spring and slide the pin out laterally. Never force: if the pin resists, consult an authorized Longines service centre or a specialist atelier such as Casati Milano. The operation requires care and should take only a few minutes.

Yes, you can use aftermarket straps on any Longines provided they match the correct lug width—in this case 21mm. Compatible straps must be sized for a 40mm case, meaning the strap thickness at the lug contact point must be appropriate. At milanostraps.it you will find a selection of artisanal 21mm straps, all compatible and customizable. Atelier Casati Milano is also available for bespoke consultations and provides an 18-month guarantee.

The lifespan of a leather strap depends on material quality, usage and maintenance. A quality alligator or calf leather, worn daily and subjected to regular maintenance (cleaning with a damp cloth, immediate drying, occasional protective treatments), lasts an average of 5 to 10 years. Japanese shell cordovan can last even longer thanks to its dense fibrous structure. Straps exposed to constant humidity, frequent perspiration or prolonged sun exposure experience reduced longevity. Casati Milano provides an 18-month guarantee on its artisanal work and recommends having your strap inspected every 2–3 years to assess any reinforcements or replacements needed.