Amazon (AMZN  ) is looking to compete with the likes of Apple (APPL  ) and Fitbit (FIT  ) with the release of Halo. Halo is capable of tracking physical activity, sleep temperature, and even emotional states.

The wearable devices market is a relatively narrow market, but a lucrative one. Currently, Apple and Fitbit dominate the market with their respective products and the various services that are paired with them. Apple leads the wearable market with just below a 30% market share, shipping 21.2 million units in Q1 2020 alone. In second is Chinese firm Xiaomi (SEHK: 1810), which holds 14% of the market.

According to Amazon, Halo has been years in the making. The company tapped into its considerable technology background but began recruiting outside health experts to help it grow its expertise to cover the necessary knowledge gaps to help it design Halo's features.

"We did a global search to find the best experts. We found cardiologists, fitness experts, and people who had spent their careers researching sleep and wellness." Said Melissa Cha, a vice president at Halo.

The actual Halo band, a wristwatch-like device, will run users $99.99, with the paired subscription service costing users an additional $3.99 a month. The device is far from an Apple Watch, lacking a clockface or any visual interface, and options such as location tracking, Wi-Fi connectivity, and many more. The device is more reminiscent of a Fitbit, in that it is more aimed towards tracking a user's health.

The band is to be paired with a smartphone to track a user's health. One of the most interesting features of Halo is rooted in the accompanying app: "body scanning." Using a smartphone, the app takes pictures of the user's body (which Amazon says must be done in tight-fitting, somewhat exposing clothing such as underwear). It then sends the images to Amazon's servers for analysis. What the app returns is a "scan" that tells the user their body fat percentage, which Amazon argues is superior to other metrics of measuring health.

The band is also capable of using microphones to listen to the tone of your voice to analyze a user's emotional state throughout the day. The app will rate a user's emotions over the course of the day, dropping them into several categories and establishing "notable moments" over the course of the day.

Amazon, no stranger to concerns of privacy, is already attempting to assuage fears of data misuse by the app and the Halo device. Amazon has stated that all features are opt-in and can be easily deactivated. Most data is not sent to Amazon's servers, and the data that is sent to servers is deleted soon after use.