The Sinn EZM 1, introduced in 1997, is a steel chronograph built as an “Einsatzzeitmesser”, or mission timer, for professional use. It has a manual-wind Lemania 5100 chronograph movement, a legible black dial with a 12-hour counter and a case designed to resist shocks. I could not confirm an official case size or water resistance from the sources found, so they are not stated here.

Sinn designed the EZM series, for Einsatzzeitmesser, for pilots and other crews who need a robust watch with a clear display. The EZM 1 was the first model in the series and set the pattern of the brand’s later technical watches.

Collectors value the EZM 1 as an early example of the Sinn tool-watch approach and for its use of the Lemania 5100, a movement with a following of its own. The original is no longer produced, although Sinn continues to make EZM-series watches.