Omega · Constellation

Strap for Constellation Co-Axial 27 Brushed Stainless Steel / Yellow Gold / Diamond / Wavy MOP

Takes 19 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width19 mm
Case diameter27 mm
Reference123.25.27.20.55.004 (aka: 12325272055004)
FamilyConstellation
MovementOmega caliber 8520 Hours, Minutes, Seconds | Date | Chronometer, Co-Axial Escapement
CaseMother of Pearl | Yellow Gold, Stainless Steel

Recommended spring bar

Spring bars Omega Speedmaster Seamaster 19mm

Technical match for lug width and diameter · lug 19 mm · Ø 1.8 mm

All Omega spring barsOpen →

The Constellation 123.25.27.20.55.004 (aka: 12325272055004), seen from the bench

The Omega Constellation 123.25.27.20.55.004 embodies the collection's stellar elegance since 1952. This reference combines yellow gold and stainless steel with wavy mother-of-pearl dial, featuring iconic griffes at 3, 6 and 9 o'clock, roman numeral bezel, and harmonious tonneau case. The 27.00 mm diameter suits slender wrists and classical micro-watchmaking proportions. The Omega 8520 Co-Axial calibre ensures chronometer-certified precision. Water resistance reaches 30 metres for daily wear. The 19 mm lug width is standard for Omega Constellation's reduced-diameter cases. The stratified mother-of-pearl dial captures light with chromatic variations depending on viewing angle.

Frequently asked questions

What is the lug width of the Omega Constellation 123.25.27.20.55.004?

The lug width is 19.00 mm (tolerance ± 0.1 mm). This measurement is standard for the Constellation women's and unisex line over the last three decades. It is measured between the inner lugs of the case, excluding the articulation pins.

Which strap material is most suitable for the Constellation 123.25.27.20.55.004?

Alligator is the most elegant choice, thanks to its natural grain that complements the Roman dial texture. Vegetable-tanned calf leather also offers immediate softness and harmonious aging. For those preferring sporty tones, FKM (Viton) rubber in black or grey maintains the elegance of the metal composition.

How do I change the strap on the Constellation 123.25.27.20.55.004?

Remove the pins securing the strap to the case lugs using a spring bar tool (extractor). Insert the new strap by aligning the lugs with the holes at the ends. Reinsert the pins with uniform pressure until you hear a click. If you have an external spring bar tool, apply gentle pressure to avoid scratching the stainless steel case.

Can I use third-party straps from other brands with my Omega?

Yes, provided the lug width is exactly 19 mm. Not all manufacturers respect this specification with precision: variations of even 0.2 mm cause friction and visual misalignment. We recommend straps from suppliers specializing in Omega watchstrap replicas to avoid incompatibility issues.

How long does a leather strap last on a Constellation 123.25.27.20.55.004?

Durability depends on the material and usage: alligator and shell cordovan with vegetable tanning maintain elasticity for 4–6 years with light daily use, 2–3 years with intensive use. Calf leather lasts 3–4 years, FKM rubber 5–7 years. Natural aging of leather is an appreciated aesthetic feature, not a defect.

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