Strap for Breitling Chronomat Automatic GMT 40 NFL Chicago Bears Edition

The Breitling Chronomat 40 GMT reference A32398C71C1A1 has a lug width of 20 mm. This measurement should be taken at the case back between the two lugs using a precision calliper, to avoid confusion with adjacent sizes such as 19 or 21 mm, which would render any strap incompatible.

The ideal strap for the Chronomat 40 GMT depends on the intended use: a vegetable-tanned alligator strap with a deployant clasp suits formal occasions and adds a bespoke dimension; a box-calf leather strap develops an authentic patina for daily wear; a technical nylon NATO strap suits sporting use and references the model's aviatory-military heritage; vulcanised rubber is the most practical option for water-related or intense sporting activities.

To replace the strap on the Chronomat 40 GMT, a spring bar tool or dedicated lever is required. The 20 mm spring bars are compressed by acting on the slots on the lugs. It is advisable to work on a soft surface to protect the case, and if in doubt, to entrust the operation to a watchmaker to avoid scratching the steel lugs.

Yes: any strap with a 20 mm attachment is technically compatible with the Chronomat 40 GMT. Milanostraps.it offers a selection of handcrafted straps in 20 mm, made to order by Casati Milano, available in alligator, calf leather, shell cordovan, nylon and rubber, with the option of a standard buckle or stainless steel deployant clasp.

The lifespan of a leather strap depends on the material, usage and maintenance. A quality alligator or calf leather strap, vegetable-tanned and kept away from prolonged exposure to water, treated occasionally with a nourishing cream, can last between 3 and 5 years with daily use, developing a distinctive patina over time. Casati Milano provides an 18-month warranty against manufacturing defects on all its straps.