A shοt timer is an electronic device (or mobile app) with a microphone that gives an audible beep for the shooter to begin and records the time of each shοt. When the shooter is finished, the display will show the time from the start signal until the last shοt. The time is usually recorded to hundredths of a second (centisecond).
Shοt timers are always used in competitive matches, but they are also very beneficial for live-fire and dry-fire practice sessions. Timing your drills can help you keep metrics to measure your improvement, identify areas of weaknesses, and test the performance of your equipment.
One nice feature of many shοt timers is the ability to set a par time. This allows a shooter to set a time limit, so the shοt timer will beep to start and beep when the time is up. A shooter can challenge herself by reducing the par time by a half second at a time during practice sessions to shave time off of drills.