Fitbit Charge 3 Fitness Activity Tracker, Graphite/Black, One Size (S and L Bands Included)

Better measure calorie burn, understand resting heart rate & more with 24×7 heart rate tracking and a battery life of up to 7 days (varies with use and other factors); charge time (0 to 100%) 2 hours
Choose from 15 plus exercise modes like run, bike, swim, yoga, circuit training and more, set a goal, and get real time stats during your workouts to see how you can keep getting better
Automatically record time spent in light, deep and REM sleep stages, see Activity trends, healthy insights, and personalized guidance in one place with Fitbit today. Operating temperature is -10° to 45° Celsius
Swim proof and water resistant to 50 meters, so you can track swims and wear in the shower; we do not recommend wearing charge 3 in a hot tub or sauna; also connect to Smartphone GPS for real time pace and distance during outdoor runs and rides
Stay connected to your day with everyday apps for weather and more and get called, text and smartphone app notifications on your wrist; small wristband fits a wrist between 5.5 to 7.1 inches; large wrist band fits a wrist between 7.1 to 8.7 inches
Radio transceiver: Bluetooth 4.0. Syncing range up to 6 meters