The most important milestone in the success story of the manufactory Zenith, was the development of the chronograph calibre El Primero. El Primero launched 1969, was the first automatic chronograph, after 7 years of construction. The first chronograph with automatic winding mechanism should actually be finished in 1965 on the 100th anniversary of the manufactory, but the engineers needed 4 years longer than originally planned. El Primero, "the first", is today one of the most precise series timepieces in the world, thanks to the automatic calibrator with 36,000 half-oscillations per hour, instead of the usual 28,800 half-oscillations. The El Primero calibre, which was presented on 10 January 1969 in two versions (with date display under the code name "3019 PHC", with moonphase and triple date display as "3019 PHF"), is even today considered a technological masterpiece . With 'El Primero', Zenith succeeded in winning the battle for the first chronograph worldwide. The cooperation of Breitling, Heuer-Leonidas, Hamilton / Büren and Dubois Dépraz with the final product: Calibre 11, "Chronomatic", could only be presented in March 1969 and was thus only "second". The El Primero movement is used both in ladies' and men's watches. The series Espada, Synopsis or Rattrapante are equipped with an El Primero. Numerous brands use the El Primero chronograph calibre. Even within Rolex ticked from 1988 till 2000 an El Primero with some modifications. Until then, Rolex did not have its own automatic chronograph calibres, certainly not in chronometer quality. That is why the largest Geneva manufacturer produced the movement, under license, world´s most famous chronograph - the "DAYTONA Cosmograph Ref.16520". In 2013 Zenith launched the chronograph El Primero Chronomaster, a further development of the calibre from 1969. With the beginning of the quartz watch era in 1970 the production of the El-Primero series was discontinued. Thanks to Charles Vermot the 'El Primero' remained to the posterity. He resisted the instructions only to build quartz watches and hid tools, machines as well as all construction and manufacturing drawings on the roof of the manufactory. At the end of 1978 Zenith was sold to the Swiss company group Dixi. In cooperation with the watchmaker Ebel the production of the 'El Primero' was resumed.

Only a few manufactories have mastered the construction of a tourbillon. The Tourbillon is considered one of the most complex complications, only a few manufactories would dare to address, otherwise Zenith. The brand with the star presented its first tourbillon model as early as 1920. In the high-precision calibre El Primero is the first fast-swing tourbillon of the world. In the recent past, Zenith (2005) presented the world's most advanced mechanical wristwatch with Tourbillon. The Gravity Control, introduced in the year 2010, built in the watch model Academy Christophe caused an even greater sensation in the watch world. Contrary to conventional Tourbillons, the escapement of this design, is always in the same position, which compensates for any friction differences - whether over short or long time.

Zenith watches have always accompanied pioneers in mankind's outstanding projects. Zenith was part of the discovery of the North and South Poles by Amundsen (1911) and accompanied Mahatma Ghandi in his freedom struggle for India. The overflight of the English Channel of Blériots also took place with a zenith on the wrist. Three years after his flight, Louis Blériot said: "I am very satisfied with my Zenith watch, which I regularly wear. I can only recommend it to anyone who is accustomed to accuracy. "Numerous expeditions, including those of Colonel John Blashford-Snell and Johan Ernst Nilsson, also included a Zenith timepiece. One hundred years after Amundsen’s expedition to the South Pole, Johan Ernst Nilson was the first person to travel from pole to pole without a motorized vehicle. He was also equipped with a Zenith chronograph, which took the time measurement of the expedition to the end of the world. 2012 the extreme sportsman Felix Baumgartner succeeded in the incredible. With an El Primero Stratos flyback on the wrist, the adventurer dared to jump out of the stratosphere. The El Primero Stratos Flyback Striking 10th - is the world's first watch that could withstand the speed of space on the edge of space. The timepiece was unimpressed by the high altitude, pressure and temperature differences and worked just as perfectly as on take-off.

Zenith relies on accuracy, reliability and precision craftsmanship. All Zenith watches are equipped with an in-house movement and are completely manufactured in Le Locle. The timepieces of the manufactory are all testimony to a boundless researcher spirit in the constant pursuit of innovation. In order to illustrate the complexity of the manufacturing process, a glance at the entrepreneurial figures is enough. In the production of an El-Primero model, 20 watchmakers are involved who process 18 different metals in a period of approximately 9 months. In addition, there are 127 milling tasks and approx. 5,000 interventions. Today, Zenith produces 32 different models for a total of five collections: Academy, El Primero, Captain, Pilot and Heritage.