MB&F
Horological Machines 57.STBL.B— lug 20mm

The MB&F Horological Machines 57.STBL.B features a lug width of precisely 20mm. This specification is established by the Swiss manufacturer and represents the standard distance between the two case lugs. To verify compatibility, measure the space between the lug attachments: it must match exactly 20mm. Using a strap with this precise measurement is essential to ensure perfect fitment without lateral play or misalignment.

There is no universally "best" strap, but rather choices coherent with the watch's design philosophy. Alligator leather of superior quality is the most elegant solution, its natural texture dialoguing beautifully with the casing's geometric complexity. Vegetable-tanned calf leather offers contemporary appeal and an evolving patina over time. Pure cotton NATO straps maintain the technical and sportive authenticity of the design. Your choice depends on personal preference and intended use: formal-elegant with alligator, contemporary with calf, sporty-casual with NATO or rubber.

Strap replacement on the 57.STBL.B follows standard procedure: use a spring bar tool to gently compress the internal spring of the pin connecting the lug to the case. Whilst holding the pin compressed, extract the previous strap and insert the new one, aligning the lug holes with the pin. Slowly release the tool to secure the new strap in position. If you lack experience, we recommend entrusting this operation to a professional watchmaker to prevent damage to the lugs.

Yes, any quality strap with a 20mm lug width is compatible with the 57.STBL.B, provided it meets construction standards. Compatibility is guaranteed by lug width: 20mm is an international standard. However, genuine quality resides in the strap's construction and materials: favour manufacturers employing full-grain leather, robust stainless steel pins, and precise stitching. An artisanal strap from a specialised maker will offer superior longevity and aesthetics compared to generic industrial products.

Leather strap longevity depends on multiple variables: material quality, tanning method, thickness, frequency of wear, and environmental exposure. A superior-quality alligator strap, worn occasionally or alternated with other straps, can last 5-7 years before replacement becomes necessary. Vegetable-tanned calf leather, being thinner and more dynamic, typically endures 3-5 years. Exposure to perspiration, humidity, UV rays, and friction accelerates deterioration. Mindful usage—avoiding prolonged humid environments and rotating multiple straps—significantly extends longevity. The natural ageing of leather, particularly vegetable-tanned varieties, is a positive aesthetic characteristic, not a flaw.