Zenith El Primero

Zenith El Primero, Zenith
Eric Kilby from Somerville, MA, USA, CC BY-SA 2.0

One of the first automatic chronographs, with a movement that beats ten times a second.

The El Primero was shown in 1969, the same year as other makers presented automatic chronographs. The high frequency made it possible to measure tenths of a second. The movement was later used by other brands too.

Materials: Steel or gold; self-winding chronograph movement

Manufacture: Made in Le Locle; the movement beats at 36,000 vibrations an hour.

Three small subdials in different colours: grey, blue and dark anthracite.

Tenths of a second on the scale around the dial.

During the quartz crisis the owners decided to stop making mechanical movements. The master watchmaker Charles Vermot hid drawings and tools in the factory, which is why the El Primero could be taken up again in the 1980s.

The balance wheel oscillates 36,000 times an hour, that is five times a second back and forth, which allows the chronograph to show tenths of a second.

Rolex used a modified El Primero in the Daytona from 1988 to 2000.