Rather than selling different sizes of its band individually, Fitbit thankfully packs two options in with each Flex, both featuring the same simple, elegant design. The smaller band has an internal diameter of about 7.5 inches, and the larger measures almost 9 inches. A single Flex sensor arrives pre-installed in the large band, with a square plastic latching system in place at one end. If you want to move to the small band, you must remove and reinstall…
