The legendary El Primero high-frequency chronograph celebrates half a century of avant-garde and precision. In tribute to its legendary destiny, Zenith is offering aficionados an anniversary boxed set containing three chronographs with emblematic tricolour counters. A reissue faithful to the first El Primero model of 1969; a Chronomaster El Primero with optimized movement; and a Defy El Primero 21 to 1/100 th of a second: the 50-piece limited-edition trilogy ‘conjugates’ high frequency in several tenses.