Defy Extreme
Zenith's flagship high-frequency chronograph line, brought back in 2021 around the El Primero 21 (Cal. 9004) dual-escapement architecture (one regulator at 5Hz for timekeeping, a second at 50Hz dedicated purely to the chronograph), resolving elapsed time to 1/100th of a second. Distinct from the integrated-bracelet Defy Skyline, Defy Extreme is Zenith's technical showcase: dramatic 45mm cases in steel, titanium, and carbon with open, mirror- or color-driven dials built to display the twin-regulator movement.