Featuring dual transmission, the HRM-Pro™ premium chest strap lets you share accurate heart rate data with your Garmin device, compatible fitness equipment and third-party training apps, such as Zwift. It also helps you improve your running form by providing running dynamics. HRM-Pro stores heart rate data when you hit the water then automatically sends it to your device after your swim. -Premium heart rate strap transmits real-time heart rate data via ANT ® technology and BLUETOOTH® Low Energy technology to communicate with Garmin devices, compatible fitness equipment and online training apps, such as Zwift -Captures running dynamics, such as vertical oscillation, ground contact time, stride length, vertical ratio and more -Stores heart rate data during swimming or other activities out of range of your Garmin watch then automatically sends data to the watch when the activity is finished -Stores steps, calories, intensity minutes and heart rate then syncs to your compatible Garmin watch when in range -Small, lightweight heart rate monitoring module is no wider than the width of the soft, comfortable strap -Battery life: up to one year