The Grönefeld One Hertz is the world's first and only series wristwatch with independent dead seconds. It features a beautiful, solid silver dial and an entirely in-house-developed movement with stainless steel bridges and exceptional fine finishing.
Dead seconds is when the seconds hand advances in full steps of one second rather than the usual smooth sweeping action of mechanical seconds. With the One Hertz, Bart and Tim Grönefeld have revived a long-neglected horological complication and repositioned it on the pedestal of high precision. Prior to the One Hertz, dead seconds in wristwatches were usually linked to constant-force devices. The Grönefeld One Hertz is unique among wristwatches in that to maximize precision, its dead seconds are powered by a secondary gear train that is independent of the gear train for the hour and minute indications.