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

The lug width of the Longines Master Collection L2.773.4.51.6 is 21mm. This is an atypical construction specification that requires purpose-built straps: it is not compatible with standard 20mm or 22mm straps. To measure the lug width accurately, align a ruler with the pins passing through the lug bar and read the free internal space.

For this 42mm chronograph, alligator leather with vegetable tanning represents the most coherent choice: the geometric texture of the scales complements the rigour of the dial, brown hues create contrast against stainless steel, and natural patina develops harmoniously with age. Valid alternatives include vegetable-tanned black vitello with fine grain for formal contexts, or textured rubber for environmental resistance.

Remove the watch from your wrist and position the case facing upward. Locate the two pins passing through each lug (one on each side). Using appropriate tool (spring bar tool or small hammer and punch), gently push the first pin from outside toward inside: the pin will exit the opposite side. Repeat for the second pin. Remove the worn strap and thread the new one, aligning the holes and reinserting the pins until you feel the locking click.

Yes, it is compatible with any strap featuring a 21mm lug width. Avoid standard 20mm or 22mm straps: these would create unacceptable lateral play. Online retailers and specialist ateliers offer bespoke leather straps in premium hides (alligator, vitello, shell cordovan) and technical rubber, all customisable in length and thread colour.

The average lifespan of a quality leather strap ranges between 3 to 5 years of daily use, varying according to environmental conditions (humidity, sun exposure, extreme temperatures). A premium vegetable-tanned leather strap develops natural patina, visually extending aesthetic longevity. A technical rubber or shell cordovan strap can reach 5-7 years. Periodic maintenance (cleaning, light conditioning) significantly extends durability.