Strap for Fifty Fathoms Bathyscaphe Stainless Steel / Grey / Black Nato

The lug width of this Fifty Fathoms is 20 mm. This measurement is precise and corresponds to the internal distance between the two lugs of the case. To verify it, position a ruler between the inner extremities of the lugs: the result must be exactly 20 mm. Do not confuse lug width with the width of the original bracelet, which may include link pins and appear slightly different.

For this model we recommend three primary options: American alligator to emphasise the sporty character and develop natural patina over time; vegetable-tanned calf for immediate comfort and the material depth characteristic of high-end watches; cotton canvas NATO for genuine diving, where washability and salt-water resistance are paramount. FKM rubber is the definitive technical choice for those intending to use the watch at depth without compromise.

The Fifty Fathoms uses open-ended lugs on the lateral extremities. To change the strap, use a dedicated spring bar tool: position the flat tip in the rear groove of the lug, push gently downward to release the spring, and slide out the old strap. Insert the new strap into the compressed spring, release pressure carefully, and verify that the strap sits securely. A straightforward operation that requires care to avoid scratching the case.

Yes, any strap with a 20 mm lug width is compatible with this watch. Blancpain lugs impose no particular constructive constraints: lug width is the only relevant parameter. We recommend choosing straps from manufacturers specialising in horological leather, where leather quality and construction precision guarantee longevity and wearing comfort. An artisanal strap in alligator or vegetable-tanned calf significantly elevates the daily wearing experience.

Longevity depends on immersion frequency and leather type. Vegetable-tanned calf, used mainly in dry or occasionally wet environments, offers 3–5 years of service before fibres degrade noticeably. Alligator, due to its denser structure, can last 5–7 years. If the watch is regularly submerged, we recommend alternating leather straps with FKM rubber options, which do not suffer from prolonged moisture. Natural leather patina is an aesthetic merit but also a sign of wear: an aged strap is beautiful, yet structurally more fragile.