Chronograph The chronograph function is a mechanism for measuring time intervals. A chronograph watch can therefore be used to time events while displaying the time like any traditional watch. Chronometer Label given to a watch which has undergone precision tests and received a certificate from an official body (COSC). Date The day of the month, displayed in a window on a watch dial at the 3 or 6 o’clock position, or within a subdial at 9 o'clock. Small seconds A hand on a sub-dial which tracks seconds typically it completes a full rotation in one minute. Tachymeter A tachymeter watch has a function for measuring speed. It is a chronograph with a graduated dial on which speed can be read in kilometres per hour based on a 1000 metre distance. Time zone function Allows the hour hand to be easily adjusted to different time zones without stopping the watch.