The Zenith El Primero is an automatic chronograph movement introduced in 1969 that beats at 36,000 vibrations per hour, faster than almost any other, which lets it measure a tenth of a second. It is one of the most important movements in watchmaking, and it is the reason to buy a Zenith. Today you will find it in three main watches: the Chronomaster Sport, a 41 mm sports chronograph with a ceramic bezel; the Chronomaster Original, a 38 mm watch in the style of 1969; and the Defy Skyline, a modern integrated-bracelet watch.
We have 318 Zenith watches in stock, from $1,760, including 101 Chronomaster and 111 Defy models.
By the numbers: Switzerland exported CHF 25.9 billion of watches in 2024, 2.8% less than in 2023, in 15.3 million pieces (9.4% fewer), according to the Federation of the Swiss Watch Industry (swissinfo.ch, 30 January 2025).
What the El Primero is
In the 1960s several Swiss makers raced to build the first self-winding chronograph. Zenith, founded in Le Locle in 1865, presented its answer in January 1969 and named it El Primero, "the first".
Two things set it apart, then and now:
- It was an integrated design, built from the start as an automatic chronograph, not a chronograph mechanism bolted onto an existing movement.
- It ran at 36,000 vibrations per hour, or ten beats a second. Most watches run at 28,800. The higher rate means the chronograph can time events to a tenth of a second.
The story that saved it
In the 1970s, with quartz watches sweeping the market, Zenith's owners at the time ordered mechanical production to stop and the tooling to be scrapped. A watchmaker at the factory, Charles Vermot, disobeyed. He hid the presses, tools and plans for the El Primero in an attic. When demand for mechanical watches returned in the 1980s, Zenith was able to start making the movement again because of what he had kept.
One of the first customers was Rolex, which used a modified El Primero in the Cosmograph Daytona from 1988 to 2000. That says a good deal about its quality.
The Zenith El Primero today
The current generation is the caliber 3600. In a traditional chronograph, the central hand takes a minute to go round. In the 3600 it takes ten seconds, so each step on the scale is a tenth of a second and you can read the result directly. The power reserve is about 60 hours.
The time-only version, the caliber 3620, keeps the high frequency and adds a small subdial whose hand races round once every ten seconds.
Zenith Chronomaster Sport
Introduced in 2021, the Chronomaster Sport is Zenith's modern sports chronograph and its best seller. It has a 41 mm steel case, 100 meters of water resistance, and a ceramic bezel engraved with a tenths-of-a-second scale. The dial has three overlapping subdials in blue, anthracite and light gray, the colors of the first El Primero.
It comes on a steel bracelet or a rubber strap, with black or white dials and versions in other colors and metals.
It suits you if you want a sports chronograph for daily wear with a movement of real distinction. Comparisons with the Rolex Daytona are inevitable, and the Chronomaster Sport costs a good deal less; our Daytona buying guide describes the Rolex.
Zenith Chronomaster Original
The Chronomaster Original is the faithful one. It takes the shape and size of the A386, the best-known El Primero watch of 1969: a 38 mm case, pump pushers, a tachymeter scale printed on the dial instead of the bezel, and the three-color subdials. Inside is the modern caliber 3600.
At 38 mm it is one of the few current chronographs that suits a small wrist, and it is slim enough to wear under a cuff. There is also a version with a triple calendar and moon phase.
It suits you if you prefer vintage proportions, have a smaller wrist, or want the watch closest to the original.
Chronomaster Open and Revival
- Chronomaster Open. A window in the dial shows the high-frequency escapement at work. It is the model for those who want to see what makes an El Primero different.
- Chronomaster Revival. Close reissues of specific historic references, made in 37 and 38 mm, often using the original production plans. They are aimed at collectors.
Zenith Defy
The Defy line is Zenith's contemporary side.
- Defy Skyline. A steel sports watch with an integrated bracelet, an angular faceted bezel and a dial stamped with a pattern of four-pointed stars. It is a time-and-date watch, not a chronograph, using the caliber 3620 with its ten-second subdial. It is made in 41 mm and 36 mm, and its bracelet swaps for a rubber strap without tools.
- Defy Skyline Chronograph. The same design with the chronograph movement.
- Defy Extreme. A large, aggressive chronograph for those who want something bold.
- Defy Revival. Reissues of the angular Defy watches of 1969.
It suits you if you want an integrated-bracelet sports watch with a movement nobody else has.
Zenith Pilot
Zenith has made aviation instruments and pilot's watches since the early days of flight, and it holds the right to print the word Pilot on its dials. The current Pilot line, renewed in 2023, has grooved dials and large luminous numerals, in an automatic and a flyback chronograph.
Which Zenith should you buy?
| You want | Look at |
|---|---|
| An everyday sports chronograph | Chronomaster Sport, 41 mm |
| Vintage style or a smaller watch | Chronomaster Original, 38 mm |
| To see the escapement | Chronomaster Open |
| An integrated-bracelet watch | Defy Skyline |
| A collector's reissue | Chronomaster Revival, Defy Revival |
Older El Primero watches
Pre-owned, you will find many earlier El Primero models, with references and names that changed often over the years: the Chronomaster of the 1990s and 2000s, the El Primero 36,000 VpH, and the Stratos and Captain lines. They use earlier versions of the movement, mostly the caliber 400 family, in which the chronograph hand takes a minute to go round in the usual way.
These can be excellent value, since they offer the same basic movement for much less. Ask about the service history: a high-frequency chronograph is a complex movement, and servicing one costs more than servicing a simple automatic.
What to check before you buy
- The caliber, on the specifications: 3600 for the current chronographs, the 400 family for earlier ones.
- The chronograph. Start, stop and reset should be crisp, and every hand should return exactly to zero.
- The size. 38, 41 and larger cases wear very differently; see our guide to choosing your watch size.
- Service history, for any watch more than a few years old. Our guide to servicing explains what is involved.
- Box and papers, stated on the listing.
For other chronographs, see our comparison of the Omega Speedmaster and the Rolex Daytona. You can browse the Chronomaster and Defy watches and every Zenith we have in stock.
Frequently asked questions
What is the Zenith El Primero?
It is an automatic chronograph movement introduced in 1969, notable for its high frequency of 36,000 vibrations per hour, which allows it to measure a tenth of a second.
What does El Primero mean?
"The first". Zenith presented it in 1969 as the first automatic chronograph movement.
Did Rolex use the Zenith El Primero?
Yes. Rolex used a modified El Primero in the Cosmograph Daytona from 1988 to 2000.
What is the difference between the Chronomaster Sport and the Chronomaster Original?
The Sport is 41 mm with a ceramic bezel and is water resistant to 100 meters. The Original is 38 mm, with the tachymeter scale on the dial and the look of the 1969 watch. Both use the caliber 3600.
Is the Zenith Defy Skyline a chronograph?
The standard Defy Skyline shows time and date only, with a small subdial that turns once every ten seconds. A chronograph version is also made.
Is Watchflix NYC an official Zenith retailer?
No. We are an independent retailer and are not affiliated with Zenith. Every watch is checked by our specialist before it ships.
