Strap for Spirit Automatic 40 Titanium / NATO

The lug width of the Longines Spirit L3.810.1.53.2 is precisely 21mm, measured between the outer shoulders of the spring bars that attach the strap to the case. This measurement is standard for 40mm sport watches and is compatible with all 21mm straps in our catalogue.

We recommend alligator in dark shades (black, dark brown) for formal wear, or vegetable-tanned leather for those who appreciate evolving patina over time. For frequent water exposure, vulcanized rubber or fabric-rubber hybrid straps deliver superior performance in humid conditions. Shell cordovan remains the choice for maximum density and longevity.

Measure the distance between the two spring bar holes on the case, from outer shoulder to outer shoulder. Use a digital calliper or millimetre ruler. Do not confuse the lug width (case aperture) with the nominal strap width: for model L3.810.1.53.2 the lug width is 21mm, even though the strap body may be 20mm.

Yes, provided the strap has a 21mm lug width. Verify that the strap was manufactured specifically for this measurement. Our artisanal leather straps are calibrated for 21mm and feature proportioned keepers and buckles suitable for the final strap width.

A quality artisanal alligator or calf strap lasts 3-5 years with moderate daily use. Shell cordovan easily exceeds 5-7 years. Longevity depends on bathing frequency, perspiration, sun exposure, and maintenance (periodic cleaning with soft cloth). Casati Milano atelier offers 18-month warranty and spring bar replacement service.