This slim tracker packs 7 days of battery, a built-in GPS, contactless payments, and 24/7 heart rate monitoring. There are more than 40 exercise modes and you get a 6-month Premium membership for more ...
From the Inspire to the Luxe, these are the best of Fitbit models compared and expert ranked ... but you can choose whatever you want to aim for. How to set up High and Low Heart Rate notifications ...