Optic sensor technology measures and displays your pulse rate with the touch of a finger; Keep track of your pulse quickly and conveniently. Calculates the pulse rate in beats per minute. High and low pulse rate target settings with an alert. Full function split stopwatch with 1/100 second resolution. Multiple mode countdown dimer with completion alarm. Time of day with calendar and daily alarm. Backlight for night time or low light use. Water resistant to 50 meters. CR 2025 Lithium battery included; One year warranty.