Strap for Master Collection 42 Moonphase Stainless Steel / Silver-Arabic / Alligator XL

The lug width of the Longines Master Collection L2.919.4.78.5 is 21 millimetres. This measurement is specific to this model and is crucial when selecting a strap: any compatible strap must have a width precisely calibrated to 21mm to fit without play into the lugs of the case.

For the Master Collection L2.919.4.78.5, the most appropriate materials are vegetable-tanned alligator for formal wear, natural calf for daily versatility, or shell cordovan for durability and evolving patina. Your choice depends on usage: formal settings favour alligator or satin calf; daily wear suits grained calf; sport-casual allows quality rubber or NATO. The ideal colour remains in dark and neutral tones (cognac brown, black, bordeaux, dark grey).

Strap replacement is accomplished via the spring bars (anse) present at both ends of the case. You will use a spring bar removal tool to gently compress the internal bar and extract the spring, allowing the bar to come free. The procedure is identical for installing the new strap: insert the bar into the holes, compress gently and secure the spring. Avoid abrupt movements to prevent scratching the case.

Yes, the Master Collection L2.919.4.78.5 is compatible with any quality strap featuring a 21mm lug width. Artisanal aftermarket straps (leather, rubber, NATO) are an excellent choice for personalising your timepiece. Always verify that your chosen strap has lugs or passants sized to 21mm: an incorrect measurement compromises both the aesthetic and mechanical integrity of the case.

The lifespan of a leather strap depends on material and usage. Quality vegetable-tanned calf resists wear for 2 to 4 years with daily wear; natural alligator can exceed 5 years thanks to its more compact structure; shell cordovan easily reaches 6-7 years. Determining factors include exposure to moisture, perspiration, UV rays and frequency of wear. Proper maintenance—periodic cleaning, drying after moisture exposure—significantly extends the strap's life.