The replacement wristband makes yours like wearable Fitbit FLEX/FORCE/CHARGE. Come with a secure clasp and a watchband-style closure to protect the band from falling off, to wear easily and to make a new style wristband for you. Made from high quality soft silicon material to have comfortable wearing experience and fit for your Fitbit One Perfectly. The Fitbit accessory is a one size fits most wrists size(165mm-230mm/6.50inch-9.06inch),adjustable watchband-style closure design. Note for fitbit ONE ONLY, Only the silicon wristband included, NO tracker.