A Fitbit band measures physical activity parameters, including calories burned, steps taken, distance walked and minutes spent active while worn on the user's wrist. It also measures amount and quality of sleep and functions as an alarm clock.
There are several models of Fitbit bands, including the Flex, Force, Surge and Charge. Other models include the Fitbit Tracker, Ultra, One and Zip, all of which are small devices worn on the body instead of as wristbands. The Fitbit Flex is the only tracker users can wear during swimming and showering, as it is waterproof. Fitbit users can earn badges for completing milestones, such as 60,000 steps taken or 100 flights of stairs climbed.