Strap for Master Collection Chronograph 40 Stainless Steel / Silver / Bracelet

The lug width of the Longines Master Collection L2.629.4.78.6 is 20mm. This measurement is taken from the inner point of one lug to the inner point of the opposite lug, parallel to the dial, using a digital calliper. The 20mm width is the construction standard for this chronograph model, ensuring balanced proportions between the 40mm case and the strap mounting.

Given the formal vocation of this chronograph, alligator remains the apex choice: its natural grain and developing patina transform the watch into an object of tactile contemplation. Excellent alternatives include vegetable-tanned leather (which ages characterfully) and shell cordovan (dense and nearly ceramic in appearance). Grained and brushed calf leather permits seasonal rotation without compromising quality.

To change the strap, use a spring bar tool to remove the pins from the lug seats. Position the tool beneath the pin, slightly toward the case exterior, and lift with controlled motion. Remove the old strap and insert the new one into the opposite seat, ensuring the pins lock fully. It is advisable to work on a soft surface (carpet or cloth) to prevent accidental case scratches.

Yes, any strap with a 20mm lug width is compatible with the L2.629.4.78.6, provided the width is precise (tolerance maximum ±0.2mm to avoid friction on pins or excessive play). It is essential not to confuse lug width (20mm) with seat thickness or strap depth. The 20mm-compatible straps from milanostraps.it are factory-verified and ready for immediate installation.

Leather strap lifespan depends on usage intensity, climate conditions and leather type. A quality alligator strap, worn daily with rotation of at least 2-3 straps, typically lasts 4-6 years. Vegetable-tanned calf tends to age more rapidly (2-4 years), whilst shell cordovan, being denser, can exceed 7-8 years. Prolonged humidity exposure significantly shortens lifespan. Quality straps can be regenerated with specific conditioning treatments, extending functional life.