Omega · Speedmaster Moonwatch

Strap for Speedmaster Replica 57 Stainless Steel / Black

Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width20 mm
Case diameter42 mm
Reference3894.50.37
FamilySpeedmaster Moonwatch
MovementOmega caliber 1861 small seconds, hours, minutes | Chronograph
Year1998 - 2003
CaseStainless Steel

Recommended spring bar

Spring bars Omega 20mm — 1.8mm diameter

Technical match for lug width and diameter · lug 20 mm · Ø 1.8 mm

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Straps for the Speedmaster Moonwatch 3894.50.37

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Speedmaster Moonwatch 3894.50.37, seen from the bench

The Speedmaster Moonwatch was introduced in 1957 and became the first watch worn on the Moon in 1969. It features the Omega caliber 1861 manual-winding chronograph movement with hours, minutes and small seconds. The lugs measure 20mm in width.

Frequently asked questions

What is the exact lug width of the Omega Speedmaster Moonwatch 3894.50.37?

The lug width of the Moonwatch 3894.50.37 is 20 mm. This measurement is not standard for 42 mm cases, so it is essential to verify that the strap you choose is compatible with this exact dimension. A 22 mm strap, although it may seem close, will not fit the case correctly.

Which strap material pairs best with the Moonwatch 3894.50.37?

Alligator, shell cordovan, and European calf are the most recommended materials. Alligator offers evolved patina and aesthetic contrast; shell cordovan evolves over time with extraordinary patina; calf allows chromatic customization without ostentation. NATO nylon straps evoke the spatial and military authenticity of the model.

How do I correctly measure the lug width before ordering a strap for the 3894.50.37?

The lug width measurement is taken from the internal point of the case, in the space where the strap end rests on the lug. Use a digital caliper or flexible ruler to measure the available space between the two symmetrical lugs. For the Moonwatch 3894.50.37 the result must be exactly 20 mm. Do not rely on external sources; always physically verify your watch.

Is an aftermarket 20 mm strap compatible with the Moonwatch 3894.50.37?

Yes, any aftermarket strap with a lug width of 20 mm is compatible with the 3894.50.37. Verify the seller's certification regarding lug width; on milanostraps.it you will find <a href="https://milanostraps.it/collections/cinturini-orologi-per-misura-ansa-20mm">20 mm straps</a> specific for this measurement, ready for shipment and customizable.

How long does a leather strap last for daily use on the Moonwatch?

A quality leather strap (alligator, calf, shell cordovan) has an average lifespan of 3–5 years with daily use, depending on the tanning and type of care. Leather ages naturally, developing patina. If the strap acquires visible cracks or the stitching fails, it is time for replacement. Artisanal ateliers such as Casati Milano offer an 18-month warranty and can replace the strap upon request.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only