Strap for Master Collection 40 Chronograph Calendar Pink Gold / Silver / Strap

The lug width of the Longines Master Collection L2.673.8.78.3 is 21mm. This measurement is specific to this model and must not be confused with more common standards such as 20mm or 22mm. The correct measurement is taken with a digital calliper from the inner edge of one lug to the other on the watch case. An incorrectly sized strap would either move loosely within the lugs or create excessive tension on the case.

The optimal strap choice for the L2.673.8.78.3 depends on usage and aesthetic preference. For pure elegance, natural alligator leather in cognac or dark brown tones creates natural harmony with the rose gold case. For those preferring a visibly stratified texture, shell cordovan develops an evolved patina over time. Vegetable-tanned leather offers the sustainable and contemporary choice. For sporting use, a high-quality canvas NATO strap with steel or rose gold buckle provides practicality without aesthetic compromise.

Changing the strap on the L2.673.8.78.3 requires a dedicated spring bar tool to compress the elastic pins securing the strap to the lugs. Position the tool from the inner side of the case and gently push to release one end, then extract the pin. Repeat on the other side. Insert the new strap by first aligning one lug, then compress the elastic pin until you hear a click confirming insertion. We recommend performing this operation on a soft surface to avoid scratches to the case.

Yes, a custom 21mm aftermarket strap is fully compatible with the Longines Master Collection L2.673.8.78.3. Bespoke custom straps are actually preferable to standard options as they allow you to adjust the total length to your wrist, select materials and colours based on your aesthetic vision for the watch, and obtain personalised stitching. The Casati Milano atelier creates 21mm custom straps with an 18-month warranty.

The lifespan of a natural leather strap varies based on material and usage. Hermès-grade alligator leather lasts 5–7 years with daily use and routine maintenance (conditioning every 6–12 months, protection from water). Shell cordovan, thanks to its structural density, can exceed 10 years of service. Vegetable-tanned leather, being more porous, requires greater care but can last 4–5 years. All straps age: the patina they develop is part of the beauty and character of your watch.