Strap for Seamaster Planet Ocean 600M Co-Axial 43.5 Master Chronometer GMT Stainless Steel / Black White / Bracelet

The lug width measures 21 mm, specific to this robust family. It is measured excluding the curved case shoulders and considering the linear internal space between the two lugs, perpendicular to the case plane.

Alligator ventralis is the choice for understated elegance; shell cordovan offers natural patina and authentic aging; vegetable-tanned calf represents the contemporary compromise with conscious aging capability.

Use a spring bar tool or consult an expert. Position the watch on a stable surface, gently push the pin from the opposite side, completely extract the spring bar support, and insert the new strap by reversing the procedure.

Yes, provided the strap is specifically sized for 21 mm. Verify that the width is consistent along the entire length and that the keeper does not generate tension on the buckle: a 0.5 mm discrepancy compromises durability and alters case positioning.

With vegetable tanning and non-aquatic use, 18–24 months. With frequent chlorine or salt water exposure, 6–12 months. FKM rubber or NATO straps offer superior durability but require buckle replacement over time.