Strap for Speedmaster Professional Moonwatch Mitsukoshi

The lug width of the Speedmaster Professional 3570.31.00 is 20 millimetres. This measurement is specific to the model and is compatible with straps built to the 20mm standard. Measurement is performed with a digital calliper, inserting the tip perpendicularly between the two lugs and reading the internal distance.

There is no universal choice, but three options excel: black alligator for timeless formal elegance, dark blue calf for subtle aesthetic contrast, shell cordovan for those who appreciate the evolution of patina over time. The choice depends on use: formal, daily wear or collecting. For humid environments, a NATO strap or fluoroelastomeric rubber strap maintains original functionality.

The lugs on the 3570.31.00 are fixed (non-folding). To change the strap, you must use a spring bar remover or consult a professional. Insert the tool into the lug hole, push the spring bar laterally to release the strap. Position the new strap by aligning it with the lug and reinsert the spring bar. If you are not experienced, consult a watchmaker to avoid scratching the case.

All straps with 20mm lug width are compatible with the Speedmaster 3570.31.00, provided they are made of certified quality leather, rubber or canvas. Milano Straps offers customisable 20mm straps in sizes, colours, initials and stitching thread. The Casati Milano atelier creates bespoke custom-made straps with 18-month warranty certification.

A quality leather strap (alligator, calf, shell cordovan) lasts an average of 2–4 years with daily use, provided correct maintenance is carried out: avoid prolonged moisture exposure, do not expose to direct UV rays, apply salt and perspiration neutraliser weekly. Shell cordovan softens over time. A vegetable-tanned leather requires stabilisation in the first weeks. With appropriate storage and rotation with other straps, durability is significantly extended.