Strap for Master Collection Date 42

The Longines Master Collection L2.665.4.51.7 features a lug width of 21mm. This measurement should be verified by placing a digital calliper perpendicular to the attachment pins, excluding any external supports. Respecting this specification is essential: a 20mm strap will be loose and unstable, whilst a 22mm strap cannot fit into the case lugs.

The ideal strap depends on usage and personal style preference. For formal elegance, we recommend dark brown or black alligator, which enhances the steel case and develops authentic patina over time. Vegetable-tanned calf leather is preferable if you desire a strap that ages gracefully. Shell cordovan strikes the balance between aesthetics and humidity resistance. For a contemporary, sporty look, high-density FKM rubber remains functional, though it sacrifices tactile quality.

You will need a Spring Bar Tool, the specialist instrument with a bifurcated tip. Position the bifurcation around one of the attachment pins and apply gentle inward pressure, moving the pin laterally. The pin will retract, allowing you to remove the old strap. Repeat on the other side. To install the new strap, align both holes and press the pin into its correct position, ensuring it is fully locked. Should your case feature specialty lug attachments, consult a professional horologist.

Yes, any strap with a 21mm lug width is compatible with the Master Collection L2.665.4.51.7. Milanostraps offers artisanal high-quality straps in genuine leather (alligator, calf, shell cordovan), customizable to your specifications. Casati Milano atelier further provides bespoke straps with direct leather selection and an 18-month guarantee, allowing you to fully valorise your chronometer.

Longevity depends on material quality and usage patterns. An artisanal alligator or calf strap, subjected to regular maintenance (gentle cleaning, annual conditioning), lasts 5–8 years under normal conditions. Shell cordovan, being denser, exceeds 10 years. Prolonged exposure to humidity, direct heat, and perspiration accelerates ageing. Rotating between two straps—a practice recommended by collectors—significantly extends each strap's lifespan whilst preserving the Master Collection from localised wear.