Strap for Fifty Fathoms Bathyscaphe Stainless Steel / White / Baby Blue Nato

The Fifty Fathoms 5100-1127-NAT features a precisely engineered lug width of 20mm. This specification is standard across the model line, proportioned to the 38mm case diameter and the weight of the Blancpain caliber 1315 in-house movement. To confirm compatibility, measure the distance between spring bar pins from inside the case.

For formal wear and daily use, alligator or shell cordovan in dark tones (mahogany, black, burgundy) creates sophisticated harmony with the satinised steel case. For direct diving or aquatic activities, technical rubber or NATO fabric straps deliver practicality and durability. Vegetable-tanned calf leather offers the optimal balance between elegance and natural colour evolution over time.

Strap replacement is accomplished by accessing the spring bars on either side of the case. Using a dedicated spring bar tool or the flat edge of a Swiss Army knife, gently push one spring bar inward until it retracts from its seat. Repeat on the opposite side. Remove the old strap and insert the new one by aligning the pins with their respective holes in the case.

Yes, provided the strap has been specifically manufactured for 20mm lug width. Most off-the-shelf strap catalogues begin at 18mm or 22mm. Casati Milano and established artisan makers offer both custom-commissioned and stock straps in this rare lug specification.

A premium handcrafted leather strap (alligator, shell cordovan, or calf) typically remains serviceable for 3–5 years under daily wear, developing an attractive patina throughout its life. Occasional use extends longevity to 7–10 years. Constant exposure to saltwater and chlorine significantly reduces strap lifespan; rubber is recommended for frequent diving. Casati Milano provides an 18-month warranty against manufacturing defects.