Strap for Admiral Chronograph GMT

The lug width of the Longines Admiral L3.670.4.56.0 is 21mm. Measure this dimension precisely between the two metal lugs of the case using a calliper or ruler. Accuracy is critical: even a 1mm variance (20mm or 22mm) would result in an incompatible strap that fails to sit properly on the case.

An alligator strap in Mississippi alligator leather, in medium brown or grey tortoise tones, represents the optimal aesthetic choice for this model. The geometric grain of alligator leather harmonises naturally with the angular geometry of the brushed steel case. A sophisticated alternative is vegetable-tanned calf leather, which develops a rich patina over time. For sport variants, a Cordura NATO strap preserves the nautical character of the watch.

Use a spring bar tool to remove the pins connecting the strap to the case lugs. Position the tool beneath each pin, lift gently to release the internal spring, and extract the pin. Repeat in reverse to fit the new strap and pins. Work on a well-lit, flat surface to avoid losing the pins. Care must be taken not to scratch the case during this operation.

Any strap with a 21mm lug width is compatible with this model. Milanostraps.it offers a curated selection of 21mm straps in alligator, calf, shell cordovan, rubber and technical fabric, customisable in length, colour, initials and stitching thread. For a bespoke experience, Casati Milano crafts artisanal custom straps with direct consultation and extended warranty.

A high-quality artisanal leather strap—alligator, calf or shell cordovan—typically lasts 4-7 years with regular wear, depending on frequency of use, moisture exposure and maintenance. Vegetable-tanned leather maintains structural integrity longer than industrial tannages. Natural ageing and patina development are desirable: the strap ages in harmony with the watch. Casati Milano offers 18-month warranty and regeneration services to extend strap longevity.