Well accustomed to technical challenges, Zenith built the Rainbow Flyback model in 1997 based on technical specifications established for the French Air Force. The result was a rugged, high-performance timepiece capable of standing up to the most extreme conditions. The brand with the guiding star now draws inspiration from this high-precision instrument in presenting an eminently sporty version named El Primero Stratos Flyback Rainbow.

When he decided to create the most reliable and accurate watches of his era, Georges Favre-Jacot brought all the watchmaking professions under one roof in 1865 in order to contribute to the advancement of production methods. The first watch Manufacture in history was born and thus forever sealed the destiny of Zenith, which would be focused on chronometric (precision-timing) performance. Almost 150 years later, the brand remains true to its founder’s visionary spirit. It is the most titled brand ever in the field of chronometry, with no less than 2,333 prizes to its credit. Its creations have laid milestones in the history of contemporary watchmaking, with over 300 patents registered for an array of more than 600 movement variations developed and produced within the Manufacture.

The world’s most accurate series-produced chronograph

In 1969, Zenith definitively put its name in the history books by presenting El Primero, the first ever integrated automatic watch, also beating at the exceptional speed of 36,000 vibrations per hour and thus displaying 1/10th second precision – an achievement that makes it the world’s most accurate series-produced chronograph to this very day. Zenith therefore naturally responded to the bid for tender launched by the French Ministry of Defence which was seeking to develop a watch for fighter pilots, especially since the brand had earned an impressive reputation in the field of aviation right from the start of the 20th century. The technical specifications to be met by the Manufacture were unequivocal: the goal was to develop a watch capable of maintaining excellent precision even in extreme conditions of use – including violent accelerations from 9 to 11 g’s, variations in pressure and temperature, as well as vibrations and magnetic fields. In rising to this demanding challenge, the Manufacture once again pushed back the boundaries of reliability and resistance to present the Rainbow Flyback model in 1997.

Reinterpreting an iconic model

Today, the brand with the guiding star draws inspiration from this landmark model in offering a reinterpretation: the El Primero Stratos Flyback Rainbow, driven by the El Primero Calibre 405 B automatic movement. While this chronograph naturally beats at the frequency of 36,000 vibrations per hour enabling 1/10th second precision, it is also equipped with a date display, a telemetric scale, and above all with the famous flyback function. Closely bound up with the world of aviation, the latter enables pilots to stop, start and restart the chronograph at a single press on the push-piece, compared with three presses required for a standard chronograph.

The 45.5 mm steel case is topped by a rotating bezel bearing an aluminium ring. The rounded sapphire crystal is shaped like an astrodome – the dome located on the fuselage’s dorsal ridge to enable astronavigation. The equally transparent engraved sapphire case-back reveals the fascinating mechanism of the world’s most accurate series-produced calibre. On the dial side, the minutes counter at 3 o’clock appears in colours enabling night-time readings in infrared-lit cockpits, exactly like the first model developed in cooperation with a fighter pilot, while the hours are displayed at 6 o’clock and the small seconds at 9 o’clock. The white superluminova hour-markers make a striking contrast with the black of the dial and case, while the chronograph sweep seconds hand stands out in red. The inner bezel ring bearing a telemetric scale creates an overall depth effect. The eminently virile and stylish El Primero Stratos Flyback Rainbow is fitted with a steel bracelet.

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REFERENCE  03.2061.405/21.M2060
Steel bracelet

  • A descendant of the Zenith military chronographs
  • Automatic column-wheel chronograph with flyback function


  • El Primero 405B, automatic
  • Calibre: 13 14’’’ (diameter: 30 mm)
  • Thickness: 6.60 mm
  • Components: 331
  • Jewels: 31
  • Frequency: 36,00 VpH – 5 Hz
  • Power reserve: min. 50 hours
  • Finishing: oscillating weight with “Côtes de Genève” pattern


  • Hours and minutes in the centre
  • Small seconds at 9 o’clock
  • 3-counter chronograph:
    • Central sweep seconds hand
    • 30-minute counter at 3 o’clock
    • 12-hour counter at 6 o’clock
    • Telemetric scale
  • Date window at 6 o’clock


  • Material: steel
  • Unidirectional rotating bezel with black aluminium disc
  • Diameter: 45.5 mm
  • Opening diameter: 35 mm
  • Thickness: 14.10 mm
  • Glass: domed sapphire crystal glareproofed on both sides
  • Case-back: transparent sapphire crystal
  • Water-resistance: 10 ATM
  • Dial: black with 30-minute counter in original colours
  • Hour-markers: Arabic numerals in SLN C1 superluminova
  • Hands: rhodiumed, faceted and coated with SLN C1 superluminova