ZENITH pushes the boundaries of mechanical architecture once again with the launch of the CHRONOMASTER Sport Skeleton. Through a smoked, openworked sapphire dial, the Manufacture from Le Locle lays bare the El Primero 3600SK calibre, transforming its high-frequency 5Hz beating heart into a continuous visual spectacle.
This new release not only brings an avant-garde aesthetic to the brand’s flagship sports line, but also marks the debut of ZENCLASP, a brand-new folding clasp with precision micro-adjustment engineered after three years of research and exhaustive testing.
📜 The Birth of an Icon: El Primero
On January 10, 1969, ZENITH unveiled the world’s first automatic, integrated high-frequency chronograph: El Primero. Developed following an ambitious project initiated in the early 1960s to commemorate the company’s centenary, the movement stood out for its ultra-thin architecture and elevated 36,000 vibrations per hour (5Hz) frequency—a technical feat that allowed time measurement with record-breaking precision down to 1/10th of a second.
Transparent Performance: El Primero 3600SK Revealed
At the core of this edition lies the El Primero 3600SK calibre. Skeletonization has been carefully executed to preserve structural rigidity and chronometric stability without compromise. The tinted sapphire crystal dial reveals the blue-finished column wheel, silicon escape wheel, and horizontal clutch, while maintaining the iconic overlapping tri-colour sub-dials (grey, anthracite, and blue) paying tribute to the 1969 original.
The collection offers 41mm stainless steel executions featuring a green or black ceramic bezel (including both a steel bracelet and an additional rubber strap), as well as a luxurious 18-carat rose gold version and a 10-piece limited edition crowned with a baguette-cut diamond bezel.
⚙️ Functional Innovation: ZENCLASP
Along with the Skeleton, ZENITH introduces the ZENCLASP. Engineered with 41 components and 10 ceramic ball bearings, it enables tool-free, on-the-wrist micro-adjustments in 2.5 mm increments up to a total of 10 mm. Validated over 600,000 test cycles, this ergonomic advancement will progressively be rolled out across the entire Chronomaster range.
Editor’s Perspective: Why the Classic Chronomaster Sport Remains King
While the technical mastery behind the openworked Skeleton is undeniable, I must admit a personal preference: **the original Chronomaster Sport introduced in 2021 with its clean, closed dial remains the absolute pillar and my favorite of the collection**.
When reviewing and photographing the classic models in the studio, the immediate legibility of the signature tri-colour sub-dials set against the crisp matte dial creates unmatched visual harmony. The new Skeleton reveals high-frequency mechanical beauty for collectors seeking drama; yet the pure contrast, balance, and legibility of the original 2021 Chronomaster Sport define the modern sports chronograph at its finest.
📸 Studio Archives
To explore the proportions, dial legibility, and studio lighting setup on the classic dial models, read our hands-on studio photography review of the Zenith Chronomaster Sport & Open.
Technical Specifications: Zenith Chronomaster Sport Skeleton
| Specification | Technical Details |
|---|---|
| Brand / Collection | ZENITH / Chronomaster Sport Skeleton |
| References | 03.3130.3600 (Black Bezel) / 03.3131.3600 (Green Bezel) |
| Case & Dimensions | Stainless steel, 41 mm diameter. Ceramic bezel with 1/10th of a second graduation. |
| Dial | Smoked openworked sapphire with overlapping tri-colour counters |
| Crystal | Domed sapphire crystal with anti-reflective treatment on both sides |
| Movement | El Primero 3600SK (Automatic integrated high-frequency chronograph) |
| Frequency / Power Reserve | 36,000 VpH (5Hz) / 60 hours power reserve |
| Water Resistance | 10 ATM (100 metres) |
| Bracelet / Clasp | Stainless steel bracelet with ZENCLASP micro-adjustment (10 mm total range). Additional rubber strap included |
| Official Price (RRP) | €16,500 / $16,700 USD (Stainless Steel Version) |
