The multi-functional Axio HR will guide you up the mountain and down again. Altimeter, barometer, thermometer, and heart rate monitor all in one. Altimeter measures cumulative ascent and descent, vertical speed, max altitude with many other great features. Digital barometer and thermometer provide accurate and timely readings. Heart rate monitor provides a 24 hour HRM chronograph, average heart rate, and target zones with audible alarm. Additional features include mineral glass lens, dual time zone, EL backlight, and water resistance to 50 meters.