Strap for Fifty Fathoms Bathyscaphe Flyback Chronograph Grey Ceramic / Blue / Blue Nato

The Blancpain Fifty Fathoms 5200-0240-NAOA features a lug width of 23 millimetres, measured between the inner shoulders of the lug attachments. This dimension is specific to this reference and requires bespoke strap construction. It is incompatible with standard 20 or 24 millimetre straps.

For a Fifty Fathoms 5200-0240-NAOA in black ceramic, we recommend either a black alligator strap with satin finishes or premium calf leather with vegetable tanning. Alligator offers natural grain that dialogues elegantly with the ceramic, whilst vegetable-tanned calf develops a distinctive patina over time. For frequent diving, a technical black rubber remains the most practical choice, preserving the watch's sporting functionality.

Strap replacement requires a delicate spring bar tool and manual dexterity. Position the tool beneath the lug terminal, apply gentle pressure to compress the internal spring, and slide the pin out. With a ceramic case, it is essential to avoid scratches: if uncertain, entrust the task to a specialised atelier such as Casati Milano, which changes straps using professional equipment and protects the case during the operation.

Yes, provided they are constructed specifically for a 23 millimetre lug width. Bespoke straps in alligator, shell cordovan, vegetable-tanned calf and technical rubber are available from specialised ateliers. Milanostraps offers a comprehensive collection of 23 mm compatible straps, crafted by artisans who understand the demands of exceptional timepieces. A bespoke strap transforms the wearing experience, allowing the Fifty Fathoms to adapt to formal or sporting occasions.

A quality leather strap with vegetable tanning, if subject to frequent saltwater contact, will last 2–3 years before displaying signs of accelerated ageing (uneven colouration, softening). If use is predominantly civilian with occasional saltwater exposure, durability extends to 4–5 years, developing a sought-after natural patina. To preserve leather, rinse in fresh water after saltwater contact and air-dry. For intensive marine environments, technical rubber remains the most durable material.