A chronograph is a type of watch that combines standard timekeeping with a stopwatch function. It allows users to measure elapsed time with precision, making it popular among athletes and professionals who need accurate timing. Chronographs typically feature additional dials or sub-dials that display seconds, minutes, and sometimes hours. The mechanism of a chronograph can be activated by pressing buttons on the side of the watch. When the button is pressed, the stopwatch starts, and pressing it again stops the timing. Many modern chronographs also include features like tachymeters for speed measurement and date displays for added functionality.