Strap for Master Collection 42 24h Stainless Steel / Black-Roman / Alligator

The lug width of the Longines Master Collection L2.718.4.51.5 is precisely 20 millimetres. This measurement, also called strap width, represents the distance between the pins on which the spring bars are fitted. You can verify it by measuring with a calliper the distance between the two opposite pins on the case, typically positioned at 6 o'clock and 12 o'clock. The standardisation at 20mm makes this model compatible with thousands of aftermarket straps available on the market.

For the Longines Master Collection L2.718.4.51.5, we recommend a natural alligator strap in cognac or dark brown tone, which enhances the silver dial and the technical character of the L704.2 movement. Alternatively, vegetable-tanned calf leather offers constructive sustainability and predictable ageing. For sporty or summer contexts, a grey pearl NATO fabric strap or black rubber strap amplifies the functional versatility of the watch whilst maintaining correct proportions with the 42mm case.

Changing the strap requires the use of a spring bar tool—a specific instrument that allows you to compress the elastic pins at the ends of the case. Position the watch on a stable surface, use the spring bar tool to push one of the pins, remove the old strap, then insert the new strap by aligning the holes with the pins. Ensure both pins are inserted firmly before releasing pressure. If you are not practised at this procedure, consult a certified watchmaker to avoid damage.

Yes, 20mm aftermarket straps are fully compatible with the Longines Master Collection L2.718.4.51.5. The aftermarket offers thousands of options in different materials: alligator, calf, shell cordovan, fabric, rubber and ostrich leather. The important thing is to verify that the lug width is exactly 20mm and that the strap is constructed with artisanal quality comparable to the watch, ensuring secure closures and refined finishes. We recommend choosing straps produced using traditional methods and natural materials to maximise aesthetic compatibility and durability.

The lifespan of a leather strap depends on intensity of use, climatic conditions and type of material. A quality artisanal calf or alligator strap, with average use (worn 4-5 days per week), has an expected lifespan of 3-5 years before replacement is necessary. Factors accelerating wear include prolonged sun exposure, high humidity and lack of regular maintenance. A shell cordovan strap can last up to 7 years thanks to fibre density. Rotation with alternative straps (alternating materials and colours) significantly extends the overall lifespan of each individual strap by reducing stress concentrated on a single piece.