Strap for Master Collection 42 Chronograph Calendar Stainless Steel / Black-Roman / Alligator XL

The lug width (lug distance) of the Longines Master Collection L2.773.4.51.8 is 21mm. This dimension is specific to the 42mm model and is determined by the distance between the case lugs. To verify it, measure the linear distance between the two spring bar holes using a digital calliper positioned perpendicular to the lugs.

For the Master Collection L2.773.4.51.8 we recommend: vegetable-tanned alligator for formal elegance and visible patina development; shell cordovan for natural lustre and superior durability; solid-coloured calf leather for daily versatility; FKM rubber or NATO fabric for sports contexts. The choice depends on intended use and desired colour harmony with the blue dial.

Strap removal requires a spring bar tool. Place the watch on a soft surface, locate the lateral spring bar pins, insert the tool into the slot beneath the pin, and push gently downward to release it. Once the pin is extracted, the strap disengages. Repeat on the opposite side. To install a new strap, position the pins into their respective lugs and ensure they click securely into place.

Yes. Any strap designed for 21mm lug width is compatible with the L2.773.4.51.8. On milanostraps.it you will find a selection of 21mm straps in various materials and colours, ready to ship or customisable at the Casati Milano atelier with bespoke sizing and finishes.

A quality leather strap, whether vegetable-tanned or shell cordovan, will last 3-5 years under moderate daily wear. Longevity depends on sun exposure, humidity levels, and frequency of wear. Vegetable-tanned leather develops a desirable patina, whilst shell cordovan maintains greater structural rigidity over time. Periodic maintenance—gentle cleaning and conditioning—significantly extends the usable lifespan.