ChronographChronographComplicated watch with a function for measuring short time periods in addition to its function for permanently displaying hours, minutes and seconds.

Small secondsSmall secondsA hand on a sub-dial which tracks seconds; typically it completes a full rotation in one minute.

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achymeterTachymeterA tachymeter is an instrument for measuring speed. It is a chronograph with a graduated dial on which speed can be read off in kilometres per hour based on 1000 metres distance.

Transparent case backTransparent case backA transparent case back - frequently made of sapphire - makes it possible to see the movement inside the watch.