Introducing The Zenith Chronomaster Open 39.5mm Watch In Steel And Rose Gold

A new case design and El Primero Caliber 3604 highlight the latest flagship at Watches & Wonders.


Zenith introduced a trio of new Chronomaster Open models at Watches & Wonders that shrink the case to a more universal size and house the latest El Primero Caliber 3600 high beat automatic. Introduced in 2003, the Chronomaster Open features an open heart design that was a first for chronographs and highlights Zenith’s high beat (5Hz) movement on the front. The dial has been redesigned with cutouts displaying the entirety of the balance and escapement, and the reworked caliber 3600 features skeletonization to better showcase both. These new Chronomaster Open watches replace the previous 42mm variant, which is now discontinued.

The case is 39.5mm in diameter and 13.1mm thick (lug-to-lug 45.2mm), which again is more wearable for the majority of wrists. There are two stainless steel models with either a black or silver dial, and a rose gold model with a silver dial. The new case design is nigh identical to last year’s Chronomaster Sport with the same crown, pushers and caseband, but without the prominent ceramic bezel. There’s a combination of brushed and polished elements, with a slim polished bezel and chamfers. A sapphire crystal protects the dial and a sapphire exhibition case back displays the latest caliber 3600.

The dial is an evolution of the original 2003 Chronomaster Open with multiple cutouts showing the balance, escapement and small seconds gears. It comes in matte black or silver with the steel case, or matte silver with rose gold. The small seconds sub-dial at 9 o’clock is made from hesalite (acrylic) with the silicon escape wheel at the upper left and balance wheel above. The two sub-dials at 3 and 6 o’clock (blue and grey, respectively), and remaining dial elements are similar to the Chronomaster Sport. Earlier El Primero movements in the Chronomaster Open line had perlage within the open heart, but the latest caliber 3604 replaces this with a contemporary, laser-engraved concentric pattern. The open-worked hour and minute hands, and all applied indices have Super-LumiNova inserts. The central chronograph hand measures 1/10th of a second, while there’s a 60-second counter at 3 o’clock and 60-minute counter at 6 o’clock.

The new in-house Caliber El Primero 3604 automatic has 35 jewels, beats at 5Hz (36,000vph) with a 60-hour power reserve. It’s a minor evolution of the latest caliber 3600 with some aesthetic tweaks to allow for a clear view of the silicon escapement and balance on the dial side. Seen from the exhibition case back, there’s an open-worked rotor with Zenith’s star in the center and the blued column wheel is clearly visible. Zenith’s caliber 3600 is a redesigned movement that honors the 50th anniversary of the original automatic El Primero column-wheel chronograph that could measure 1/10th of a second via the central chronograph hand.

The two steel Zenith Chronomaster Open models (ref. 03.3300.3604/21.M3300 black dial, ref. 03.3300.3604/68.M3399 silver dial) retail for CHF 9,900 and the rose gold model (ref. 18.3300.3604/69.C922) retails for CHF 19,900. Not bad for new high-beat chronographs from Zenith, especially the steel models. Visit Zenith here.