Strap for Seamaster 300 Co-Axial Master Chronometer Yellow Gold / Lapis Lazuli

The lug width is 21mm. This measurement is specific to the 41mm Seamaster 300 and determines the maximum strap width compatible with the watch. Measuring it correctly with a digital caliper between the two lugs (in the inner part where the strap is inserted) is essential to avoid incorrect purchases.

For yellow gold, we recommend dark brown alligator (cognac or havana) or grey pearl satin calf with a yellow gold deployant clasp. If the dial is blue, a dark blue alligator creates visual harmony. Bordeaux shell cordovan is ideal for those seeking dramatic color aging over time.

The Seamaster 300 features straight lugs. To change the strap: remove the watch, position a spring bar tool under the metal lug, press gently to release the elastic pin, remove the old strap and insert the new one. This operation requires care to avoid scratching the yellow gold case.

Yes, as long as they have a 21mm lug width. On milanostraps.it you will find artisanal straps in alligator, calf and shell cordovan specifically made for this size. The Casati Milano atelier also offers custom personalization with direct selection of leathers and thread color.

The lifespan depends on the material and tanning process. Vegetable-tanned calf lasts 5-8 years with daily use. Natural alligator reaches 10-15 years. Shell cordovan is the most resistant (20+ years). The natural aging of leather is part of the beauty—with the Casati Milano Atelier you have an 18-month guarantee on manufacturing defects and maintenance advice.