Strap for Horological Machine N°3 HM3 Sidewinder Red Gold

The MB&F Horological Machines 31.RTL.B features a 20 mm lug width, a modern standard requiring purpose-designed straps. Measurement should be carried out with a digital calliper positioned perpendicularly between the inner shoulders of the lugs, taking care not to confuse lug width with strap thickness.

For the 31.RTL.B we recommend black alligator for formal contrast with rose gold, vegetable-tanned calf for aesthetic warmth, or heavyweight cotton NATO for sportive interpretation. Your choice depends on usage: classical, versatile, or technical. Each material dialogues distinctly with the sculptural architecture of the case.

Strap change is performed via spring bars or specific fasteners, depending on case configuration. Position your watch carefully on a protective support, use a dedicated tool to lift the spring bar from one lug simultaneously, and slide the old strap free. Insert the new strap and ensure the spring bar engages fully on both sides. If uncertain, consult a specialist atelier.

Yes, any strap with 20 mm lug width is compatible. MB&F employs universal attachment standards, allowing you to select from our bespoke straps or other manufacturers, provided they respect the 20 mm specification. Always verify compatibility with your retailer.

A quality leather strap with vegetable tanning typically lasts 3–5 years under moderate daily wear. Lifespan depends on UV exposure, humidity, and frequency of use. The leather develops a patina narrating your history, whilst fibres naturally thin. A NATO strap in technical textile has similar duration but with distinct wear patterns. Regular maintenance with natural oils extends product longevity.