Chronographs are watches with a stopwatch function. Most have two or three sub-dials for measuring minutes and hours. When used in conjunction with specialized scales on the watch dial, it can perform many different functions, such as determining speed or distance (tachometer and telemeter). Some chronographs can time more than one event simultaneously, which is called split-seconds chronograph, or rattrapante in French and Doppelchrono in German. Some chronographs feature a function that allows resetting the timing session by only pressing one button, a function named Flyback or Retour en Vol (in French).
Chronographs usually feature two pushers (one to start and stop, one to reset) but architectures with one pusher also exist, under the name Monopusher.
Chronographs exist since the early 1800s and all were hand-wound movements. In 1969, three manufacturers (Zenith, Seiko and Heuer/Breitling/Hamilton) coincidentally launched the first automatic chronograph movements.