Amazon has announced Halo, a combination subscription service, app, and fitness wearable that promises to use some of the same technology the company developed for Alexa to add a new dimension to personal health tracking—tone of voice.

The product’s announcement copy makes the case that “strong social connections are just as important to long-term health as adequate sleep, being fit, having a good diet, or even not smoking.”

Using machine-learning-driven speech processing, the device intermittently records your voice and analyzes its tempo, rhythm, pitch, and intensity to make judgments about “the positivity and energy of your voice” where “positivity is measured by how happy or sad you sound, and energy is how excited or tired you sound.”

The app gives you daily summaries of how you sounded throughout the day. Amazon argues that having access to this information will help you understand how you sound to others, and to diagnose social problems in your life, like if you are being tense with your family in the evenings because you are stressed at work during the day.

Making a privacy point, Amazon points out that the device doesn’t start listening until you opt in, and all samples are processed locally on your phone and deleted when the processing is complete.

The device has no screen and does not send frequent notifications. Sensors include an accelerometer, a temperature sensor, a heart rate monitor, and two microphones. You can press a dedicated button to disable or re-enable the microphones at will. In addition to the differentiating Tone feature, the band and service track many of the usual suspects for fitness wearables: sleep, activity, and body fat percentage.

Amazon promises water resistance and battery life up to seven days.

The Halo band comes in three sizes—small, medium, and large—and three colors: winter + silver, blush + rose gold, and black + onyx. The wearable will cost $64.99, and it’s currently in “early access” status on Amazon’s storefront, meaning that you have to request access. Membership is $3.99 per month after a 6-month free trial. The app is available on both iOS and Android.

Amazon hedges in its press release that the above pricing is specific to the early-access period, but the company doesn’t say how much it will cost once it leaves early access, or when that will happen.

Listing image by Amazon