Zenith · Class

Strap for Class Sport El Primero Stainless Steel / Black / Bracelet

Takes 18 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width

18mm

18 mm straps All Zenith

Lug width18 mm

Case diameter40 mm

Reference03.0510.400/24.M510

FamilyClass

MovementZenith caliber El Primero 400 hours, minutes, small seconds | date | Chronograph, column wheel

CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

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

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Straps for the Class 03.0510.400/24.M510

Selected for the 18 mm lug width · workshop selection

All 18 mm straps →

The Class 03.0510.400/24.M510, seen from the bench

The Zenith Class 03.0510.400/24.M510 is a refined sports-elegant chronograph featuring the legendary El Primero 400 automatic caliber with 36,000 vph frequency. The 40mm stainless steel case houses a clean dial with subdials at 12, 9, and 6 o'clock positions, plus date window. An 18mm lug width accommodates interchangeable straps, and the transparent caseback reveals the movement's intricate architecture.

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