Strap for Master Collection Retrograde

The lug width of the Longines Master Collection L2.715.4.78.6 is 20 millimetres. This is the distance between the two lugs of the case and represents the only valid measurement for selecting a compatible strap. It is essential to measure this dimension accurately using a digital calliper or ruler, completely excluding the lugs and measuring only the free space between them. A measurement error of even 1-2 millimetres results in mechanical and visual incompatibility.

The best strap depends on intended use and aesthetic preferences. For formal or dress wear, we recommend genuine alligator in medium brown tones (cognac, havana) which naturally complements the blue dial and gilt hands. For robust daily wear, shell cordovan is the ultimate investment: it offers near-infinite durability and develops extraordinary patina over time. Traditional calf leather represents the ideal compromise between versatility and value. For light sporting contexts, a 20mm canvas NATO transforms the watch into a worry-free companion.

Strap replacement is a straightforward operation requiring a precision tool: a spring bar removal tool. Procedure: 1) Position the watch with the strap facing upwards; 2) Insert the tool tip into the thin opening between the case and spring bar to compress the internal spring; 3) Gently extract the spring bar from one side, then the other; 4) Align the new strap holes with the lug ends; 5) Reinsert the spring bars until they click into position. If uncertain, our Milan experts can perform the change by appointment at Casati Milano.

The Longines Master Collection L2.715.4.78.6 accepts any strap with a lug width of 20 millimetres and total length between 115-130 millimetres. On milanostraps.it you will find a complete selection of artisanal 20mm straps in alligator, calf, shell cordovan, vegetable tannin, NATO and rubber, all customisable in length, initials and stitch thread colour. We recommend always verifying that the spring bar is removable (standard for this case) and that materials are authentic with certification of origin.

Duration depends on material, usage and maintenance. A robust calf strap with daily wear typically lasts 2-4 years before showing significant wear. Alligator, owing to lower density, tends to last 1.5-3 years with equal use. Shell cordovan, being extremely dense, can exceed 10 years without replacement. The critical factor is exposure to water, perspiration and prolonged direct sunlight, which accelerate ageing. To maximise longevity, we recommend rotating at least two straps, allowing the unused one to rest, and occasionally applying natural-based conditioning balm. Casati Milano offers an 18-month warranty on all artisanal straps and maintenance assistance via WhatsApp.