The Zenith Defy El Primero 21 was introduced at BaselWorld 2017. Building upon the brand's rich chronograph tradition, it is powered by the new El Primero 9004 movement, capable of measuring up to 1/100 of a second. In addition, it marks the return of the Defy name for Zenith.
The Zenith Defy El Primero 21 Ultraviolet reference 97.9001.9004/80.R922 was added to the collection in 2020.
Self-winding movement with cam-actuated chronograph capable of measuring up to 1/100 of a second. The chronograph runs on its own escapement system, with a balance wheel operating at 360.000 bph. The power reserve for the chronograph is 50 minutes, and it is wound by hand. The balance for the regular timekeeping runs at 36.000 bph and is wound either by hand or through the oscilating weight. Both balance springs are made of 'carbon-matrix carbon nanotube composite'. The central hand makes one rotation every second; at 12:00 there's a power reserve indicator for the chronograph.