Zenith Defy El Primero 21

When you are looking for an ultra-precise chronograph this Zenith Defy El Primero 21 might be the one for you. The central seconds hand of the chronograph fully rotates one time per second which brings timing to a higher level: up to one hundredths of a second.

Zenith launched their first precision chronograph in 1969. It was the El Primero automatic with integrated column-wheel chronograph beating at a high 36,000 vph. This enables accuracy up to one tenth of a second and came with a COSC certification. The Zenith Defy El Primero 21 features a new movement, the El Primero 9004. It still beats at 36,000 vph however they made some adjustments.

The Zenith Defy El Primero 21 comes in three versions

To measure one hundredths of a second the chronograph movement needs to act at warp speed: 360,000 vph, or 50 Hz. Which means is uses ten times more energy. And it shouldn’t interfere with the smooth running of the watch. For that reason Zenith uses two independent ‘gear boxes’. One for the time and one for the chronograph. They have their own transmission and escapement system and they are not coupled with a clutch. Now the time has about 50 hours of power-reserve, the chronograph 50 minutes. Therefor the chronograph has its own power-reserve indicator at the 12 o’clock position so you know when to wind it.

The Zenith Defy El Primero 21 has some 1960s styling and comes in three versions. One in titanium with silver-toned dial, one in titanium with open-worked dial. And a black one in ceramicised aluminium with open-worked dial. The one with silver-toned dial is the most retro model and features a small seconds hand at 9 o’clock. The open-worked models are even more fascinating to look at. But the most fascinating part is the chronograph seconds hand. Watch it run in the video below.