Strap for Master Collection 42 Moonphase Stainless Steel / Blue - Diamond / Bracelet

The Longines Master Collection L2.919.4.97.6 features a lug width of 21 millimetres. This measurement is specified by Longines and represents the internal space between the two terminal bars where the strap is attached. Accurate measurement requires the use of a digital calliper positioned between the two inner lugs, not across the full width of the lug itself.

Alligator leather with vegetable tanning is the most elegant choice for the Master Collection, owing to its geometric grain and flexibility that conveys refined luxury. Alternatively, vegetable-tanned calf leather offers a softer approach and develops a natural patina over time. For daily and sporting use, a high-density nylon NATO or FKM rubber provides superior functionality and durability.

The procedure requires a spring bar tool. Position the tool in the dedicated slot and gently lift the upper terminal to release the elastic bar securing the strap. Remove the old strap and insert the new one, ensuring the spring bar clicks firmly into the terminal. Repeat the operation on the opposite lug. This process should be performed with precision to avoid damaging the case.

Yes, provided the lug width is precisely 21 millimetres and the strap is crafted to high-quality standards. Artisanal aftermarket straps, such as those from Casati Milano, are fully compatible and offer the opportunity to personalise the watch's aesthetics without compromising construction integrity. Always verify compatibility before purchase.

Durability depends on the tanning method and usage patterns. An alligator or vegetable-tanned calf strap worn daily offers a lifespan of 3-5 years before requiring colour restoration or leather conditioning. With regular maintenance—light brushing and protection from excessive humidity—leather can remain functional for longer periods. An FKM rubber strap, conversely, provides almost indefinite resistance to atmospheric agents.