To get an edge on the competition you need to train hard and train smart. With the digital Timex Ironman Race Trainer heart rate monitor you get the necessary data to improve your performance. 10-workout memory gathers elapsed time and heart rate data when you run the watchs chronograph or interval timer so that you can track progress. Interval timer offers a 5-interval countdown timer that can repeat up to 99 times interval timer is useful when workouts include different segments, such as a run/walk method. Each segment in the interval timer can be set for both heart rate zone and duration, so you can get time and effort guidance during a workout. Upload data from the watch to your home computer by purchasing the Timex Data Xchanger USB device sold separately analyze the data using the Timex online training website. 2-way wireless communication link provides seamless wireless communication and data transmissions between the watch and other ANTSport devices. Preset your desired heart rate exercise zone an alarm will warn you when you have gone of your zone. Average heart rate is given for total workout, for each lap and for total time in your zone. Provides total calories burned and displays percentage of maximum heart rate. Recovery heart rate timer measures your heart rate after a timed recovery, during or after your workout. Maximum heart rate zone calculation automatically sets your 5 training zones 1 manual zone included. Digital transmission protects your data from cross talk with other heart rate monitors and electronic interference from exercise equipment. Water-resistant hatch in heart rate sensor accommodates quick and easy battery changes. INDIGLO night-light illuminates the display for easy use at night. 100-hr. chronographs with lap and split options. 50-lap memory with average heart rate per lap. 100-hr., 3-mode countdown timer 3 alarms can be set as daily or weekly.