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

The lug width of the Blancpain Fifty Fathoms 5100B-1110-NAOA is 20 mm. This dimension is proportional to the 38 mm case diameter and requires straight-lug straps (not curved) for perfect fit and zero play.

For this model, vegetable-tanned alligator or shell cordovan straps are recommended for daily-elegant use, or rubber and NATO for frequent diving. Teak or black alligator creates chromatic harmony with the dark blue dial, whilst rubber maintains grip in wet and saline environments.

The strap is replaced by gently extracting the spring bars from the lugs using a dedicated tool. Align the lugs (20 mm width), insert the new bars into the lug and strap holes, then secure with controlled pressure. If unsure, entrust the task to a certified watchmaker or Casati Milano service.

Yes, all straps with 20 mm lug width and straight lugs are compatible. MilanoStraps offers a dedicated collection of alligator, cordovan, rubber and NATO fabric straps specifically sized for this lug width. Always verify the lug diameter before ordering: it must be exactly 20 mm.

A quality leather strap (alligator or shell cordovan) on this watch lasts 3–5 years with daily use and proper maintenance. If frequently exposed to salt water, lifespan reduces to 2–3 years; in this case, a rubber strap is preferable. Vegetable-tanned leather ages with fascinating patina, whilst cordovan develops natural lustre over time.