Strap for Navitimer 8 Automatic 41 Stainless Steel Swiss Air

The Breitling AVI A1731S1A1B1X1 has a lug width of 21mm — a specific measurement of the AVI line, not interchangeable with the more common 20mm or 22mm. To verify it, measure the inner distance between the two lugs using a digital calliper at the narrowest point.

For the AVI A1731S1A1B1X1, a vegetable-tanned Louisiana alligator strap strikes the most balanced combination of formal register and technical character. Alternatively, a box calf strap for everyday wear or a ballistic nylon NATO for outdoor use, both in 21mm.

The strap is removed using a 21mm springbar tool. With a flat-head screwdriver or a dedicated springbar tool, compress the spring bar laterally until it clears the lug hole. No case disassembly is required and the operation can be completed in a matter of minutes without specialist equipment.

Yes. Any strap with a 21mm attachment and standard spring bars is compatible with the AVI A1731S1A1B1X1. Milanostraps.it offers a curated selection of handcrafted 21mm straps, with options for bespoke leather, stitching and buckle customisation through the Casati Milano service.

Longevity depends on the leather and frequency of use. A quality vegetable-tanned alligator strap, maintained periodically with neutral wax, typically lasts 3–5 years. A standard calf strap has a useful life of 1–2 years with daily wear. Casati Milano straps carry an 18-month guarantee against manufacturing defects.