
The standard frequency in watchmaking is 28,800 beats per hour, or 3 Hz. The most celebrated modern example of a high-frequency movement is the original Zenith El Primero, beating at 36,000 vph, or 5 Hz. Developed in 1969, it is still used today and represents the standard in high frequency.

Back in the 1940s, Observatory Chronometer competitions in Switzerland awarded prizes to the most accurate watch movements, and the winners were inevitably the movements with the highest frequencies, but the high speed created a lot of wear on the delicate components of a watch escapement. Today, advancements in component materials have helped solved that. Silicon hairsprings and balance wheels, titanium components and other secret weapons make it possible to create escapements in mechanical movements that are almost indestructible, with more precisely engineered gears and pinions that hold their shape with minimal friction and more precise gear meshing, even when molded into tiny components. In some cases, there is no longer any need for lubrication. These advancements have made it possible for watchmakers to build escapements that vibrate at much higher frequencies and track elapsed times to 1/100th of a second.

The new-generation twin-barrel El Primero 9004 has a balance spring made of carbon-matrix carbon nanotube composite, a Zenith-patented material that is resistant to gravity and temperature fluctuations. It is anti-magnetic to 15,000 gauss. In addition to central hours and minutes, there is a small seconds sundial at 9 o’clock, a 1/100th-second central chronograph hand, a 30-minute totalizer at 3 o’clock, seconds and 1/10th second at 6 o’clock, and a percentage indication of the chronograph power-reserve at 12 o’clock. A patented chronograph-reset control mechanism composed of three heart pieces and an exclusive starter mechanism allow simultaneous resetting of the seconds as well as tenths and hundredths of a second.
The El Primero caliber 9004 is COSC-certified and has a 50-hour power reserve for the time and a 50-minute power reserve for the chronograph. The 44-mm case is available in three options: titanium, priced at $9,600; titanium with an openworked dial for $10,600; and ceramicized aluminum with an openworked dial for $11,600.