CTB

Chronograph watches can measure and display elapsed time. Usually three subcounters on the dial display the elapsed seconds, minutes and hours.

Split-seconds chronographs can measure intermediary time thanks to another second hand which is able to catch up with the other running hand if needed.

The dead seconds is a hand that jumps forward when the second has elapsed. Generally the jump of the second hand is a distinctive feature of a quartz watch but in mechanical watchmaking, this function is a technical feat.