Features: Displays current heart rate zone readings. Features heart rate zone alert function: Heart Rate Monitor beeps and icon flashes when heart rate is below or above target training zone. Tracks calories burned. Stopwatch timer counts up to 29hr 59min 59sec with 1/100th second precision. 12/24-hour clock with alarm function and calendar. EL backlight for easy viewing in lowlight conditions. Water resistant (up to 164 feet/50 meters) and shock resistant (up to 3 feet/1 meter). Requires one CR2032 batteries (included).