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

The lug width is 21mm. This measurement is determined by the distance between the two case attachment lugs and defines the internal diameter of the compatible buckle (18mm).

For the platinum model, dark brown or black alligator (formality and refined aesthetics), burgundy shell cordovan (harmonious aging), or grey calf leather (versatility) are recommended. The choice depends on the intended use and wearing context.

The strap is replaced by removing the horizontal spring bar that connects the lug to the case, using a specific tool (spring bar tool). The operation takes a few minutes; if you are not experienced, it is advisable to consult an expert to avoid damage to the platinum case.

Yes, there are aftermarket straps designed for watches with 21mm lug width. Milanostraps offers a dedicated collection of handcrafted straps in various materials, customizable in size and finish, ideal as alternatives to the original integrated bracelet.

A quality leather strap, vegetable-tanned, has an average lifespan of 3-5 years with daily wear; it depends on humidity exposure, cleaning frequency, and the chosen material. Shell cordovan and alligator are more resistant than traditional calf leather.