This premium heart rate strap tracks runs, swims and more. It transmits real-time heart rate data over ANT+ connectivity and Bluetooth Low Energy technology, giving you more training options. Consistently receive accurate heart rate on your Garmin device, in online training apps such as Zwift or even the compatible fitness equipment at the gym. In addition to heart rate, HRM-Pro captures running dynamics that can help you improve your form. That includes metrics such as vertical oscillation, ground contact time, stride length, vertical ratio and more. The device stores heart rate data during swimming or other activities while your watch is out of range, then sends that data to your watch once the activity is finished. It will also store steps, calories and intensity minutes, then sync them to your watch as well. HRM-Pro features a small, lightweight heart rate monitoring module that is no wider than the width of the soft, comfortable strap. And dont worry about running out of juice. The user-replaceable coin cell battery lasts for up to 1 year.