Features: Displays current heart rate (does not display continuously). Tracks calories burned. Stopwatch timer counts up to 99hr 59min 59sec 59milisec with 1/100th second precision. 12/24-hour clock with alarm function and calendar. EL backlight for easy viewing in low-light conditions. Water resistant up to 164ft/50m. Shock resistant up to 3ft/1m. Requires one CR2032 battery (included).