Whether youre training for a world-class event or just want to get data from your daily workout, the Garmin Forerunner 405CX heart rate monitor will help you get the results you desire. Forerunner 405CX features a new advanced calorie-consumption formula that calculates calories burned based on micro changes in the users heart rate during aerobic activity. Developed by excercise scientists and world-class athletes, the formula more accurately calculates calories burned than previous methods. Forerunner 405CX comes with 3 wristbands to accommodate nearly every wrist size the 2 included form-fitting webbing wristbands comfortably fit large and small wrists. GPS satellites accurately calculate speed, distance and pace information GPS receiver provides rapid first fix and is sensitive enough to acquire signals under cloud cover. Navigation capabilities let you mark locations, find locations or navigate back to the starting point. Chest-strap heart rate monitor helps you train in your target zone to optimize performance. Compete against the Forerunners Virtual Partner to help improve your times simply set time, distance or speed goals and race against a runner icon on the display. ANT wireless technology lets you automatically transfer data between your computer and Forerunner without even taking the watch off compatible with Mac and PC computers. Data can be analyzed by downloading free Garmin Training Center GTC software onto your computer or by using the Garmin Connect community website. Garmin Connect community website tracks your time, speed, distance and calories burned store and share routes with other Forerunner users on the website. Website also allows users to categorize and design workouts based on activity-prior workouts can be saved by day and week designations.