Strap for Chronomat 40 GMT Stainless Steel / Green - Germany

The lug width of the Breitling Chronomat 40 GMT P323981A1LA1 is 20 mm. This measurement is taken between the two lugs using a millimetre calliper, measuring the internal slot into which the strap fits, not the external width of the case.

For the Chronomat 40 GMT, a vegetable-tanned alligator strap is the most coherent choice given the watch's technical and formal character, developing a genuine patina over time. Smooth calf leather suits intensive daily use, while rubber or ballistic nylon NATO straps are better suited to sporting or marine environments.

The strap is replaced using a fine-tipped spring bar tool, applying gentle leverage to the spring bar housed within the lugs. Work on a soft surface to avoid scratching the case. No specialist tools are required, though entrusting the operation to a watchmaker or the Casati Milano atelier is recommended to preserve the lug finish.

Yes. Any 20 mm strap with standard spring bars is technically compatible with the Chronomat 40 GMT P323981A1LA1. milanostraps.it offers a curated selection of handcrafted 20 mm straps verified for compatibility with Breitling lugs, requiring no adapters.

The lifespan of a leather strap depends on the material, care and frequency of use. A quality vegetable-tanned alligator strap, kept away from excessive moisture and perspiration and regularly treated with conditioning cream, can last between three and seven years whilst retaining structural integrity. Shell cordovan, owing to its density, typically outlasts alligator under intensive daily wear.