The Zenith El Primero Chronomaster reference 03.0240.4021 is a vintage-inspired automatic chronograph from the early 2000s, part of Zenith’s iconic El Primero collection, which features the legendary high-frequency movement first introduced in 1969. This model, often referred to as the Chronomaster Open, showcases an open-heart design that reveals the beating escapement of the movement through a dial cutout, blending classic aesthetics with modern horological precision.
| Has Box | Yes |
|---|---|
| Has Papers | No |
| Model (Cert) | El Primero Chronomaster |
| Case size | 45mm |
| Case material | Stainless Steel |
| Movement type | Automatic |
| Condition | This timepiece has undergone a thorough inspection of water resistance, accuracy, functionality and condition to determine the level of reconditioning required to meet our strict standards. It has als |
| Crystal type | Sapphire Crystal |
| Gender | Male |
| Make (Cert) | Zenith |
| Origin | Switzerland |
| Strap material | Black Leather |
Unleash horological brilliance with the Zenith El Primero Chronomaster Open ref. 03.0240.4021, a 40mm stainless steel icon honoring the 1969 original—the world’s first automatic chronograph. Its sleek case, ideal for wrists up to 7.5 inches, boasts a warm black dial, sapphire crystal, and transparent caseback revealing the legendary El Primero Caliber 402. With 50m water resistance, it’s built for daily adventures with timeless flair.
The Caliber 402 hums at 36,000 vph, delivering 1/10th-second chronograph precision and a 50-hour power reserve via column-wheel mastery. The open-heart dial at 10-12 o’clock showcases the escapement’s dance, with luminous hands and markers ensuring clarity.


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