Fitbit ankle use compatible bands for fitbit flex & fitbit one activity trackers. Only compatible with fitbit flex and fitbit one. Tracker not included. Newer version available: Go to https://www.amazon.com/dp/B075W6H9CJ for the NEWEST version of this product. Now available in 3 sizes! Easy to use: Our fitbit ankle compatible bands have an easy slide-in pouch for your fitbit flex or fitbit one activity tracker. Adaptable to YOUR life: Fitbit bicycle users and fitbit stroller parents love counting their activity while hands are stationary. Avoid fitbit rash: Ankle fitbit users avoid the wrist rash some customers have experienced due to water becoming trapped under their fitbit bracelet. Versatile Sizing: Fits ankles from 8.75in to 11.75in circumference. Fitbit flex XL users have also shared that they love adjusting the snaps to use this as a fitbit flex wristband xl replacement band.