Zenith Chronomaster El Primero 'Shadow' Revival 97.T384.4061/21.C822 collection_seamaster The black dial includes a

The black dial includes a magnified day/date calendar and LumiBrite hands and markers

In the 1940s

the excellence test

meeting ISO standards for scuba diving to depths of up to 300 meters

Zenith Chronomaster El Primero 'Shadow' Revival 97.T384.4061/21.C822 collection_seamaster The black dial includes aA timepiece shrouded in mystery. Its existence has eluded collectors and Zenith collaborators alike for decades. As the legend goes, in 1970, not long after Zenith debuted the groundbreaking El Primero calibre, the manufacture had produced a prototype of a manual winding chronograph, housed in a blackened steel case a rarity for the time. Only a handful of this spectral prototype was made, but the model was never officially produced or commercialized.