After last year's celebration of its 160th, ZENITH returns with a makeover for one of its favourite signatures: the CHRONOMASTERS Sport model. But not only does the CHRONOMASTER Sport get a new look, it also has a new beating heart, one in the form of the El Primero 3600.

When the original El Primero movement was introduced in 1969, not only was it the world’s first automatic chronograph, but it also set a new standard of precision in mechanical watchmaking. While chronographs of that era were made of a combination of a timekeeping movement and the chronograph complication (this adds height and increased interfaces of the parts), the El Primero is a unified system of the two. As an integrated system, it ran at 36,000 vibrations per hour (5Hz); able to measure to 1/10th of a second.

In 2019, the improved El Primero 3600 came onto the scene and you can see its complexity (blue column wheel, horizontal clutch, a silicon escape wheel) via the openworked sapphire dial of the CHRONOMASTER Sport Skeleton. The tri-colour overlapping counters remain and hearken to the original 1969 El Primero. Sweeping the face are the baton-style applied markers and faceted hands that glow in the dark thanks to the Super-LumiNova coating.

There’s also ZENITH's new tool-free folding clasp that allows for micro-adjustments and the watches are water resistant at 10 ATM. Available in four versions: two stainless steel cases in either a green ceramic bezel with grey-toned counters, and a black ceramic bezel with the grey, anthracite and blue tri-colour counters; an 18-carat rose gold case, with a black ceramic bezel, and finally, a 10-piece limited edition rose gold case that's set with 50 baguette-cut diamonds.