Strap for Flagship 30 Stainless Steel - Yellow Gold / White - Roman / Bracelet

The lug width of the Longines Flagship L4.374.3.21.7 is 15 millimetres. This dimension is specific to this model, determined by the compact proportions of the 30mm case. To measure the lug width correctly, position a ruler on the inner part of the case between the two lugs, from edge to edge, without applying pressure.

For the Flagship L4.374.3.21.7, alligator leather represents the ideal formal choice, especially with vegetable tanning that develops natural patina over time. Alternatively, superior-quality calf leather offers softness and aesthetic restraint. For versatility towards informal contexts, a vulcanised rubber strap in black or navy blue allows extended wearability whilst maintaining elegance.

Strap replacement requires removal of the spring bars that secure the strap to the lugs. Using a dedicated spring bar tool or small screwdriver, press the bar from the inner side until the spring releases, then extract the old strap. Insert the new strap, reposition the bar and verify the lock. A straightforward operation, though recommended for those with prior experience.

Yes, it is possible to use quality aftermarket straps with 15mm lug width. Milano Straps offers bespoke leather straps customisable for this dimension. It is essential to verify that the strap is constructed specifically for 15mm lugs, as this is not a standard size. Casati Milano atelier crafts custom straps with personal selection of leathers and 18-month warranty.

The lifespan of a leather strap depends on material and use. An alligator or quality calf leather, with vegetable tanning, has an expected life of 3–5 years in regular daily wear. Longevity increases if the strap is alternated with others, limiting exposure to perspiration and humidity. A deployante buckle in stainless steel protects the strap from continuous compression and extends its lifespan. Casati Milano guarantees their straps for 18 months.