Featuring dual transmission, the hrm-pro plus premium chest strap lets you share accurate heart rate data with your garmin device, compatible fitness equipment and third-party training apps, such as zwiftit also helps you improve your running form by providing running dynamics, including vertical oscillation, ground contact time, stride length and more. Plus, for indoor runs, hrm Pro plus sends pace and distancehrm-pro plus stores heart rate data when you hit the waterin swim/run events or triathlon and then automatically sends it to your device when you reach dry landduring team sports, it also monitors steps, calories and intensity minutes then syncs with your garmin watch via the garmin connect appgo on, and push your performance to the next level while wearing one of our most comfortable heart rate straps yet ? With a battery you won?T need to replace for up to one year (based on 1 hour training per day)battery is standard cr2032 li-ion cellunit weight is 59gwater rating is 5atmstr