Fitbit wristbands and cases for an existing Fitbit tracker are available at Fitbit.com and on Amazon.com. Cases and bands are sold for different Fitbit models, including the Flex, One and Zip trackers.
Amazon.com and Fitbit.com offer cases and replacement wristbands in a variety of colors. The wristbands come in both small and large sizes. The small wristband fits wrists between 5.5 and 6.5 inches around, and the large wristband fits wrists between 6.5 and 7.9 inches around. According to Fitbit, the wristbands are made of a sturdy elastomer material that is similar to the material used in typical sports watches. Clips for the One and Zip trackers are made of silicone and metal.