Amazon has entered the health gadget market with an innovative fitness band called Halo. Unlike other existing wearable devices, Amazon Halo Band doesn’t have a screen. Instead, a sensor module is hidden under the band. The app that goes along with it comes with the usual set of fitness tracking features including activity and sleep tracking, plus two innovative ideas: using your camera to create 3D scans for body fat and listening for the emotion in your voice. In addition, a Halo subscription will offer a suite of “labs” developed by partners. They’re short challenges designed to improve your health habits – like meditation, improving your sleep habits, or starting up basic exercise routines.