All Specs Lots of fitness trackers can measure your calories burned, heart rate, and steps. With the Halo, Amazon wants to give you greater visibility into your overall health, along with actionable insights to help improve it. Priced at $99.99 for the band plus $3.99 per month for a membership (after a six-month free trial), the Halo does an excellent job of monitoring your activity and sleep, and its companion app gives you access to a wide range of workouts and wellness programs. In addition, the Halo has the ability to analyze the tone of your voice to tell you how you sound to other people, and measure your body fat percentage based on images taken with with its app. These two features are a bit gimmicky, but the Halo band is otherwise useful if you're looking to move more and improve your shut eye.