Strap for Seamaster Diver 300M Quartz 36.25 Stainless Steel / Yellow Gold / White / Bracelet

The lug width is 20mm. This means the strap must have a width of exactly 20mm at the attachment point on the case. It is important to measure precisely using a digital caliper on the inner shoulder of the lug, as oversized straps (22mm or 24mm) create structural tension, while undersized straps generate play and premature spring bar failure.

For the bi-metallic version in yellow gold and steel, we recommend deep brown alligator with medium grain for a formal-elegant aesthetic, or caramel-toned shell cordovan for sophisticated contrast. If you intend to use it for actual diving, black FKM rubber remains the only option with certified chemical resistance. For daily-sport use, vegetable-tanned calf leather ages beautifully, developing natural patina.

The change requires a specific tool to remove the spring bars (spring bar removal tool). Position the watch on a stable base, gently release the spring bar from the inner shoulder toward the center of the case, lift the already-mounted strap and insert the new one by aligning the holes to the lug. Reinsert the spring bar until you feel a dry click of locking. If you are not experienced, a professional watchmaker takes just a few minutes without any risk to the case.

Yes, provided they are certified for 20mm lug width. Milanostraps.it offers artisanal straps compatible in leather, rubber and fabric, customizable in length, initials and stitching thread. Atelier Casati Milano by appointment creates bespoke straps with personal choice of leathers and 18-month warranty. Avoid unknown brands that do not respect construction tolerances.

A quality artisanal alligator or shell cordovan strap lasts 3-5 years with moderate daily use and proper maintenance (monthly cleaning, biannual conditioning with natural waxes, air drying after water contact). Vegetable-tanned leather ages better, developing natural patina, while FKM rubber does not wear but may lose elasticity after 4-6 years of continuous sun exposure. Durability depends on the environment (humidity, chlorine, salt) and maintenance habits.