Zenith SA is a Swiss luxury watchmaker. The company was started in 1865 by Georges Favre-Jacot at the age of 22, in Le Locle in the canton of Neuchâtel. Zenith was purchased by LVMH in November 1999, becoming one of several brands in its watch and jewellery division which includes TAG Heuer and Hublot.
The El Primero calibre was first released in 1969, went out of production in 1975 and was resurrected in 1986.
It was one of the first automatic chronograph movements and has a frequency of 36,000 vibrations per hour (5 Hz). Zenith’s El Primero movement was used by Rolex from 1988 to 2000 for the Rolex Daytona chronograph. The El Primero movement’s high rate allows a resolution of 1⁄10 of a second and a potential for greater positional accuracy over the more common standard frequency of 28,800 vibrations per hour (4 Hz). The El Primero was honoured with a 2012 release of the El Primero Stratos Flyback Striking 10th, limited to 1,969 pieces (in honour of the original 1969 release date), that housed the same 36,000 vph movement and a sub-dial measuring in tenths of a second to make a complete rotation every ten seconds.