Technical Archive

Longines
Flagship L4.374.4.18.6— lug 15mm

Longines Flagship L4.374.4.18.6: 15mm strap. Alligator, box calf, shell cordovan and rubber, cut and stitched in Milano. Choose your leather.

Flagship 30 Stainless Steel / White / Bracelet

Artisanal Note

"This model requires a precise 15mm lug width to preserve the original sartorial balance."

Technical Specifications

Longines L4.374.4.18.6
Lug Width
15 mm

The essential strap measurement.

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Reference

L4.374.4.18.6

Movement

Longines caliber L592.5 Hours, Minutes, Seconds | Date | Chronometer

The Heritage

The Flagship represents one of Longines' classic lines characterized by elegant design and essential functions. It is powered by the automatic L592.5 caliber with chronometer certification, displaying hours, minutes, seconds, and date indication. The case features 15mm lugs and an integrated bracelet as per reference code L4.374.4.18.6.

FAQ

What is the lug width of the Longines Flagship L4.374.4.18.6?

The lug width of the L4.374.4.18.6 is 15mm, a non-standard dimension requiring bespoke strap production. Correct measurement is performed with a digital calliper, measuring the internal distance between the two lug pins on the watch case.

What is the best strap for the Longines Flagship L4.374.4.18.6?

For the L4.374.4.18.6 we recommend grey-taupe alligator, vegetable-tanned calf in cognac or burgundy tones, or suede leather. Choice depends on usage: alligator for formal occasions, vegetable-tanned calf for daily wear with evolving patina, FKM rubber for summer. Milano Straps produces all options tailored to 15mm width.

How do I change the strap on a Longines Flagship L4.374.4.18.6?

Remove the original straps by operating the lug pins with a suitable tool (pin remover). Slide each pin outward until fully detached. Insert the pins into the new 15mm-width strap, ensuring they sit firmly without play. For bespoke straps, verify compatibility with passants and deployante buckle.

Can I use an aftermarket compatible strap on the Longines Flagship L4.374.4.18.6?

Yes, provided the lug width is exactly 15mm. Non-certified Longines straps remain compatible if manufactured to the 15mm standard. Milano Straps guarantees total compatibility on customised straps and provides 18 months warranty on materials and craftsmanship.

How long does a leather strap last on a Longines Flagship L4.374.4.18.6?

Durability depends on material and usage: suede leather 2-3 years with regular wear, alligator 4-6 years, vegetable-tanned calf 3-5 years. Factors such as humidity, perspiration, and sun exposure accelerate ageing. Milano Straps recommends replacement when the deployante buckle no longer secures properly or the material thins excessively.