Strap for Master Collection 40mm Power Reserve Stainless Steel / Black-Roman / Alligator

The lug width of the Longines Master Collection L2.908.4.51.7 is 21mm. This dimension represents the distance between the two spring bar pins mounted on the case where the strap attaches. Precise measurement with a digital calliper or millimetre ruler ensures complete compatibility with any aftermarket strap designed for this specific width.

For the Master Collection L2.908.4.51.7 in stainless steel, straps in natural alligator leather, vegetable-tanned calf, or shell cordovan represent the most sophisticated choices. Alligator creates refined contrast with the metal case; vegetable-tanned calf develops patina over time; cordovan underscores the dress-oriented character of the timepiece. Avoid excessively casual straps to preserve the watch's formal identity.

Strap changing requires a spring bar tool to remove the attachment pins. Position the watch on a stable surface, access the pins from the lugs, push the small metal button inward to release the old strap, then insert the new one (always 21mm) until it clicks into place. If unfamiliar with the procedure, have a qualified watchmaker or the Casati Milano atelier perform the operation.

Yes, any strap with a 21mm lug width is perfectly compatible with the Master Collection L2.908.4.51.7. Quality artisanal aftermarket straps often offer greater customisation than original Longines straps, allowing choice of leather, colour, thickness, and finishing. Always verify the lug width before purchase.

The lifespan of a natural leather strap varies depending on the tanning method and usage: typically 3–5 years with moderate daily wear, up to 7–10 years with proper care and occasional wearing. Vegetable-tanned leather ages beautifully, developing patina; cordovan is more durable; alligator requires greater protection from moisture. Casati Milano offers 18-month warranty on bespoke straps and can regenerate leather upon return post.