Two pillars of Swiss design—Zenith watchmaking and USM modular furniture—have collaborated on a limited edition that reimagines what might have occurred had their paths crossed in the 1960s. The Defy Chronograph USM, unveiled at Geneva Watch Days 2025, takes the 1969 Defy case design and equips it with the El Primero chronograph movement that debuted the same year. The result is what Zenith terms "imagined heritage"—a watch that never existed but feels entirely plausible within the context of both brands' design philosophies.

The collaboration draws from a specific moment in Swiss design history. USM patented its modular furniture system in 1965, built around chrome-plated steel tubes, connector ball joints, and coloured panels. Four years later, Zenith introduced both the angular Defy case design and the El Primero chronograph movement. While these innovations developed independently, they shared common ground: geometric clarity, functional purpose, and enduring relevance. The new watch explores what Fritz Haller, designer of the USM system, and Zenith's team might have created together during that period of Swiss modernism.

The stainless steel case measures 37.3mm, smaller than contemporary Defy models but true to period proportions. The octagonal case shape features a 14-sided bezel—design elements that echo USM's modular aesthetic of precise angles and industrial elegance. Pump-style chronograph pushers maintain vintage authenticity while ensuring tactile operation. The watch comes on the "ladder" bracelet originally designed by Gay Frères in 1969 specifically for Zenith, completing the period-correct appearance. Water resistance is rated at 10 ATM.

The dial adopts USM's signature colour palette across four limited editions: USM Green, USM Pure Orange, USM Golden Yellow, and USM Gentian Blue. Applied square hour markers feature horizontal grooves that reference USM's industrial design language. Three overlapping chronograph subdials in silver display fine concentric circular finishing with rhodium-plated azuré patterns—a detail that subtly references USM connector handles. The chronograph seconds hand incorporates a miniature USM ball joint at its tip, filled with Super-LumiNova. When the chronograph runs, it reveals a hidden Zenith star beneath.

The El Primero 400 movement continues the legacy of the 3019 PHC introduced in 1969. Operating at 36,000 vibrations per hour (five Hz), it provides the high-frequency precision that defined Zenith's chronograph innovation. The automatic movement features column wheel architecture, silicon escapement components, and 55-hour power reserve. Functions include central chronograph hand, 30-minute counter at three o'clock, 12-hour counter at six o'clock, and date at 4:30. Through the sapphire caseback, the rotor displays côtes de Genève decoration flanked by both Zenith and USM logos.

The Defy Chronograph USM represents a thoughtful exploration of Swiss design principles rather than a straightforward vintage reissue. By combining Zenith's chronograph expertise with USM's modular aesthetic, the collaboration creates something that feels both historically grounded and conceptually coherent. For collectors interested in design history beyond horology, the watch offers a tangible connection between two streams of Swiss modernism. Whether this "imagined heritage" resonates will depend on appreciation for both brands' contributions to their respective fields. The Hour Glass welcomes those interested in examining this intersection of watchmaking and industrial design.