Strap for Seamaster Diver 300M Master Co-Axial 42 Stainless Steel / Black / Bracelet

The lug width of this model is 20.00 millimeters. This measurement is the standard construction specification for the Seamaster Diver 300M in steel with a 42mm case, and is compatible with 20mm straps from any brand. You can verify it by measuring with a digital caliper between the lugs on the case, from outer ring to outer ring.

The choice depends on your personal style. For formal elegance, vegetable-tanned alligator leather with natural patina emphasizes the ceramic modernity of the watch. For everyday versatility, grained calf leather offers a refined and durable appearance. If you intend to preserve the theoretical diving capabilities of this model, fluoroelastic FKM rubber is resistant to salt water and chlorine. Ballistic nylon NATO straps maintain the tactical-military element inherent in the Seamaster DNA.

The Seamaster Diver 300M uses bayonet lugs (fixed on the case). For strap replacement: (1) place the watch on a soft cloth; (2) extract the buckle bayonet from the right lug by gently pushing inward; (3) slide the strap outward; (4) insert the new strap by aligning it with the left lug, then secure the bayonet in the right lug until it clicks. Caution: never force the lugs; the movement should be smooth.

Yes, absolutely. A custom 20mm strap mounts exactly like an original one, provided it has been constructed respecting the exact 20mm width and that the end links are compatible with Omega lugs. Casati Milano crafts custom straps with personal choice of leather, thread color, and customized length, ensuring perfect fit to your wrist and optimal comfort level.

A fine leather strap (alligator, calf, shell cordovan) worn daily with ordinary maintenance typically lasts 3–5 years. Durability depends on: frequency of wear, exposure to moisture and perspiration, periodic care with specific balms, and construction quality of the stitching. A handcrafted strap from Casati Milano, made with selected leathers and Goodyear welted construction, guarantees 18 months of protection against manufacturing defects and maintains structural integrity well beyond this period with basic maintenance.