The Fitbit Charge HR is an advanced fitness tracker, smartband, and heart rate monitor in one meant for continuous, all day wear. With a 5 day battery life, the Charge HR can continually monitor various health markers like your heart rate, sleep time, calories burned, and floors climbed without needing to be constantly recharged. The Charge HR also works with a smartphone app and website to provide you with an all inclusive tool to take control and improve your health. Using bluetooth technology, the Charge HR also pairs with your smartphone to alert you of incoming calls.