How did you sleep? Find out with the Index™ Sleep Monitor . Comfortable, lightweight and worn on the upper arm, this smart sleep band can capture sleep-tracking and recovery metrics - including sleep score, sleep stages and HRV status - so you can better understand how your body recovers each night (data presented is intended to be a close estimation of metrics tracked). Using skin temperature, advanced women’s health tracking can provide more insight into your menstrual cycle , including better period predictions and past ovulation estimates (this feature is not intended to support conception, contraception or birth control and is not a medical device). If you wear a compatible Garmin smartwatch during the day, your data will seamlessly sync via the Garmin Connect™ app for more insight into your health and fitness . Plus, get up to 7 nights of battery life.