· Utilize 24x7 heart rate to accurately track calorie burn, resting heart rate & heart rate zones during workouts· Track all day activity, including steps, distance, hourly activity, active minutes and calories burned. The Fitbit inspire band is made of a flexible, durable elastomer material similar to that used in many sport watches, and fastens with a peg and loop· Automatically track sleep plus due to the heart rate feature and get more insights into your light & deep sleep stages· Enjoy up to 5 days of battery for daily progress without constant charging. Varies with use and other factors. Charge time (0 to 100 percent): 2 hours· Automatically and conveniently record workouts like walks, swimming & bike rides in a snap with smart track. Stores heart rate data at 1 second intervals during exercise tracking and at 5 second intervals all other times· Radio transceiver: Bluetooth 4.0. Fitbit inspire and inspire HR are water resistant to 50 meters. We do not recommend wearing inspire or inspire HR in a hot tub or sauna. Operating temperature: 14 degree to 113 degree Fahrenheit. Maximum operating altitude: 28,000 feet