Strap for Seamaster Diver 300M Master Co-Axial 42 Titanium - Bronze Gold / Green / Bracelet

The lug width of the Seamaster Diver 300M reference 210.90.42.20.10.001 is 20mm. This dimension corresponds to the distance between the two case lugs and is determined by the geometry of the lugs in proportion to the 42mm diameter. Accurate measurement is performed by positioning a digital caliper perpendicular to the inner edges of the two lugs.

For the Seamaster Diver 300M in titanium, we recommend vegetable-tanned alligator (develops interesting patina), traditionally tanned calf leather (dark brown or black for contrast), or rubber/fluoroelastomer if actual marine use is anticipated. Ballistic nylon NATO straps offer practical versatility. Shell cordovan, while fascinating, is not recommended for frequent diving.

Strap replacement requires a spring bar tool and removal of the locking pins present in the lug holes. Position the tool under the pin, apply gentle pressure until the internal spring releases, and remove the old strap. Reinsert the pin in the new strap, aligning it perfectly and verifying the tightness. In case of discrepancies in lug width or doubt, consult the Casati Milano atelier.

Yes, all straps with a 20mm lug width are mechanically compatible. However, it is essential to verify that the thickness (ideally 1.4-1.6mm for structured leathers) and the width of the attachments fit without play or stress on the titanium lugs. Milano Straps offers 20mm straps tested for optical and functional compatibility with the Seamaster Diver 300M.

Durability depends on the material: vegetable-tanned alligator resists 3-5 years with maintenance (regular cleaning, sun protection); tanned calf 2-4 years depending on UV exposure; rubber 2-3 years before losing elasticity; nylon NATO 5-7 years. Factors such as diving frequency, chlorine, constant humidity, and direct sun significantly reduce these periods. Casati Milano warranty is 18 months on custom straps.