The El Primero Striking 10th chronograph embodies the grand return of the Manufacture Zenith to the technical values that have forged the brand’s success. Unequalled to date, the legendary El Primero calibre was the world’s first automatic chronograph to beat at a rate of 10 vibrations per second. It is the most sophisticated mechanical ‘motor’ and the one boasting the highest degree of precision, since the vast majority of other mechanical movements beat at 8 vibrations per second at best.