Chronomaster Open

The Zenith Chronomaster Open offers a distinctive take on the legendary El Primero chronograph, showcasing an open dial that reveals the beating heart of its high-frequency movement. Introduced as a modern evolution within the Chronomaster lineup, it’s notable for the partially skeletonized display at 9 o’clock—an aesthetic and technical highlight that sets it apart from classic closed-dial El Primero models. This feature not only draws the eye but also allows a glimpse of the escapement in action, a rarity in Swiss chronographs at this price point.

Reference numbers like 03.3300.3604/69.M3300 (steel case, silver dial) and 03.3300.3604/21.M3300 (steel case, black dial) are most sought after, with dial color and bracelet or strap options driving price variation. Earlier Open models used a larger case and different movement architecture, so the current 39.5mm case brings the watch closer to vintage El Primero proportions while improving wearability. The open aperture design is unique to the Open line, so it’s essential to confirm you’re looking at the correct reference if you want the visible escapement.

Inside beats the El Primero 3604 automatic chronograph caliber, offering a 1/10th second chronograph function and a 60-hour power reserve—an upgrade over many standard El Primero movements. Water resistance is rated at 100 meters, making this a versatile daily wear option. When buying, inspect the movement through the open dial for smooth, high-frequency (5 Hz) operation, and confirm the presence of original bracelet or strap, as Zenith-signed hardware adds value for collectors seeking a complete set.