Zenith · El Primero

Strap for El Primero Chronomaster Skeleton 45 Ceramic / Strap

Takes 22 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width22 mm
Case diameter45 mm
Reference49.2520.400/98.R578
FamilyEl Primero
MovementZenith caliber El Primero 400B hours, minutes, small seconds | date | Chronograph, column wheel
Year2016
CaseCeramic

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the El Primero 49.2520.400/98.R578

Selected for the 22 mm lug width · workshop selection

All 22 mm straps →

The El Primero 49.2520.400/98.R578, seen from the bench

The El Primero Chronomaster Skeleton 45 Ceramic (ref. 49.2520.400/98.R578) features a 45mm ceramic case and the Zenith caliber El Primero 400B movement. This automatic chronograph operates at 36,000 beats per hour, enabling centisecond precision measurement. The watch includes hours, minutes, small seconds, date, and complete chronograph functions with column wheel mechanism. The 22mm lug width is precisely engineered to fit the ceramic case geometry without gaps.

Frequently asked questions

What is the lug width of the Zenith El Primero 49.2520.400/98.R578?

The lug width of the Zenith El Primero 49.2520.400/98.R578 is 22mm. This measurement is determined by the geometry of the 45mm ceramic case and its original attachment lugs. To verify accurately, position a digital calliper perpendicularly between the two attachment points, measuring from the inner centre of one lug to the inner centre of the other.

Which strap type is recommended for the Zenith El Primero 49.2520.400/98.R578?

For this technical chronograph, straps in genuine alligator with fine grain are recommended—offering sober elegance and exceptional durability—or vegetable-tanned calf leather that maintains colour legibility over time. For professional applications, FKM rubber or technical cordura provide waterproofing and minimal maintenance. The choice depends on intended use and desired aesthetics.

How do you change the strap on the Zenith El Primero 49.2520.400/98.R578?

Strap replacement requires a spring bar removal tool. Position the watch on a cushion with the strap facing upward, locate the two access holes to the lugs, insert the tool to compress the spring bar and extract it downward. Repeat on the opposite side. Installation of the new strap follows the reverse procedure. Extreme care is recommended to avoid damaging the ceramic case.

Is there a compatible aftermarket strap for the 49.2520.400/98.R578?

Yes. Milanostraps offers a dedicated collection of 22mm-compatible straps, available in numerous materials and colours, customisable in dimensions, initials and stitching thread. All straps are specifically dimensioned for this lug width and ready for fast dispatch. For highly specialised requirements, the Casati Milano atelier creates bespoke straps with personal leather selection.

How long does a leather strap last on the Zenith El Primero 49.2520.400/98.R578?

Longevity depends on leather quality and use. A strap in high-quality alligator or vegetable-tanned calf has an average lifespan of 3-5 years under normal wear, extendable with regular maintenance and rotation with other straps. Constant exposure to moisture, perfumes and detergents reduces lifespan. FKM rubber straps endure longer, up to 7-10 years, maintaining superior structural integrity.

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