In 1997, Zenith produced a professional pilot chronograph designed to meet the needs set fourth by the French Ministry of Defence. Specifically, the watch needed to remain highly precise, regardless of the g-forces (up to 11 gs), as well as resisting variations in pressure, temperature, and magnetic fields. The result was the Zenith El Primero Stratos Flyback Rainbow, made for the elite fighter pilots of the French Air Force.

For 2014, Zenith has reissued a new version of the El Primero Stratos Flyback Rainbow. It is presented in a 45.5 x 14.10 mm stainless steel case with a rotating bezel with aluminum insert and a 0-60 scale. The flange is printed with a telemetric scale to calculate the speed of sound in air. The wearer can use it to calculate the distance between the observer (pilot) and a situation that is being observed both visually and audibly.

Inside, is the El Primero caliber 405B self-winding movement that features Zenith’s famous 5Hz movement that allows 1/10th of as second chronograph precision. The flyback function of the chronograph allows the pilot (or wearer) to start, stop and restart the chronograph instantly with a single push on the pusher, as opposed to three presses on a typical chronograph. This allows the chronograph to be operated much easier while in the act of flying a plane, for example.

The minute counter at 3 o’clock has been produced with colors that enable night-time reading in infrared-lit cockpits. At 6 o’clock is the 12-hour chronograph counter, with a date aperture located underneath. A small seconds display is located at 9 o’clock.

The black dial creates an easy to read contrast between the white Superluminova hour and minute hands, as well as on the red chronograph minute and second hands.

The Zenith El Primero Stratos Flyback Rainbow comes with a clear caseback and is paired with a steel bracelet. Water-resistance is 100 meters.