Strap for Flagship 40 Stainless Steel - Yellow Gold / Silver / Bracelet

The lug width of the Longines Flagship L4.984.3.79.7 is precisely 21 millimetres, measured between the inner edges of both watch lugs. This specification is unique to this reference and is not compatible with 20mm or 22mm straps, so accurate measurement using a digital calliper positioned perpendicularly at the midpoint of the lug is essential.

Alligator leather remains the most harmonious choice: its fine grain dialogue perfectly with the aesthetic balance of the 40mm case and sunburst dial. Alternatively, vegetable-tanned calf leather offers austere character with natural patina evolution, or Japanese shell cordovan for those seeking exceptional durability (8-10 years) with periodic conditioning.

Use a spring bar tool to carefully extract the pins from the case lugs with precise, gentle rotation. Position the tool into the pin slot, rotate slightly to release internal spring tension, then withdraw the bar from the lug holes. Repeat on the opposite lug. Align the new strap's eyelets with the lug holes and reinserve the pins using reverse motion until the spring clicks into position.

Yes, provided the stated lug width is precisely 21 millimetres. Bespoke quality straps manufactured to this specification respect standard industrial tolerances (±0.5mm) and ensure correct spring bar functionality. It is advisable to request internally reinforced eyelets (copper or brass) to preserve structural integrity over time.

A quality alligator or calf leather strap constructed for daily use maintains structural integrity for 4-6 years with regular maintenance (soft cloth cleaning, moderate sun exposure). Japanese shell cordovan extends this lifespan to 8-10 years. Longevity also depends on frequency of use, ambient humidity, UV exposure, and conditioning with natural oils specifically formulated for watchmaking leather.