Strap for Navitimer 8 B35 Automatic Unitime 43 Stainless Steel / Black / Bracelet

The Breitling AVI AB3521U41B1A1 features a lug width of 23mm. This is a non-standard measurement in contemporary watchmaking, requiring straps specifically manufactured to this width. For an accurate measurement, a digital calliper should be used between the two lugs at the narrowest point of the opening.

For the Breitling AVI AB3521U41B1A1, a matte hornback alligator strap in tobacco or cognac tones is the most coherent choice given the watch's military heritage. Vegetable-tanned calf leather offers a sportier alternative that develops a distinctive patina over time. A 23mm nylon NATO strap remains faithful to the model's original aeronautical purpose.

The strap on the Breitling AVI AB3521U41B1A1 is replaced by removing the spring bars from the lugs using a dedicated spring bar tool with a fine tip. Given the 23mm lug width, it is essential to use spring bars of the correct length — typically between 20mm and 22mm effective length — to ensure proper tension within the lug holes.

Yes, aftermarket straps specifically manufactured for the 23mm lug width of the Breitling AVI AB3521U41B1A1 are available. Milano Straps offers a dedicated selection in alligator, calf leather, shell cordovan and NATO, all cut precisely to 23mm to ensure full compatibility with the original case lugs.

The lifespan of a leather strap on the Breitling AVI AB3521U41B1A1 depends on leather quality and daily use. A high-quality alligator or shell cordovan strap can last between 3 and 7 years with regular maintenance — leather conditioner every 3 to 4 months and protection from moisture. Vegetable-tanned calf, whilst less water-resistant, develops a distinctive patina that improves its appearance with wear.