Strap for Master Collection Date 42

The lug width of the Longines Master Collection L2.665.4.51.6 is exactly 21 millimetres. This measurement is taken between the metal pins (the lugs anchoring the strap to the case) and tolerates no deviation. A strap with a different width, even 1 millimetre off, will not seat correctly.

There is no universal best choice, but rather an informed choice based on use and personal aesthetic. For classical elegance, we recommend natural alligator in vegetable tanning or shell cordovan: both age magnificently. For daily versatility, soriano calf offers initial suppleness and develops a patina that narrates its wearer's history. For sports contexts, a NATO textile strap or technical rubber provides robustness and practicality.

The strap is removed by acting on the lateral pins (often with a dedicated tool, a strap changer): apply pressure on the opposite side until the pin snaps out of its seat. Once both pins are extracted, the old strap releases. Insert the new strap by aligning it with the slots and snap the pins into the seats until you hear the click of closure. If unsure, consult a qualified watchmaker.

Yes, provided the lug width is 21 millimetres. Any 21mm strap—whether from a known brand or artisanal maker—will work mechanically. Aesthetic quality depends on leather selection, stitching, and finishing. High-quality artisanal straps, such as those from Casati Milano, often exceed standard alternatives in durability, patina development, and customisation.

Durability depends on leather type and usage. Vegetable-tanned alligator resists 5-7 years if worn daily; shell cordovan may last 10+ years thanks to its density. Natural calf has shorter durability (3-5 years), but develops a unique patina. Failure typically occurs via stitching breakdown or wear in the fastening zone (deployante). Regular maintenance (cleaning, conditioning) significantly extends strap life.