For more than five decades, the El Primero has been known for what it measures. Introduced in 1969 as the world’s first automatic integrated high-frequency chronograph calibre, its 5 Hz beat set a technical standard and established Zenith’s reputation for precision. With the CHRONOMASTER Solo Sport, the maison keeps that beat and removes the chronograph, giving the CHRONOMASTER collection its first three-hand watch and a daily role for a movement long associated with timing events.
Zenith builds this idea on familiar ground. The 40mm stainless steel case keeps its proportions compact, and the ceramic unidirectional bezel adds a sporting edge without committing the watch to a single pursuit. Crown protectors frame the screw-down crown, which contributes to 20 ATM of water resistance, enough for a sudden downpour or a weekend swim. The result sits between a sports watch and a dress watch, which suits a piece intended for everyday wear.
Inside, the El Primero 3620, derived from the 3600 chronograph movement, continues to run at 5 Hz (36,000 VpH). A silicon escapement, a stop-second mechanism, and a bi-directional winding system with a star-shaped rotor deliver 60 hours of power reserve, so a watch left on the nightstand over the weekend still runs on Monday morning. With the chronograph pushers gone, the display is reduced to hours, minutes, a central seconds hand and, on most versions, a date. The frequency remains, and the seconds hand carries it.
With no chronograph to show, the dial takes on the task of expressing high frequency. Zenith developed a pattern exclusive to this watch: a repeated 45° Z motif engraved into ceramic, intended to translate the movement’s rhythm into a surface. It appears on a sunray white dial and on polished black and brown versions, and it extends to the counterweight of the seconds hand. A “shark tooth” minute track drawn from Zenith’s archives frames the edge, while faceted hands and indexes coated with Super-LumiNova SLN C1 keep the legibility after dark. The white version suits sunlit weekends, black adapts to nearly any dress code, and brown brings warmth to autumn wardrobes. Purists can choose the black version without a date for a cleaner dial.
The same attention reaches the wrist. The three-link steel bracelet closes with ZENCLASP™, the folding clasp Zenith presented at Watches and Wonders 2026. Lifting a small cover lets you adjust in 2.5mm steps across a 10mm range without tools, so you can loosen the fit after a warm lunch or tighten it before a morning run. The clasp comprises 41 components and took three years to develop, with testing equivalent to more than 10 years of use and over 600,000 openings and closings.
Zenith has focused on the details an owner encounters every day, from the beat of the movement to the fit of the clasp. In doing so, it extends a heritage built on precision to a watch designed to be worn without occasion.
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