First wristband (patent pending) for Fitbit ONE activity tracker that turns your ONE into wearable Fitbit FLEX/FORCE/CHARGE. 2016 Upgraded version. More secured, smaller, lighter. Lost proof design. Turn you Fitbit One into a watch. Personalize your wristband to match your daily style with these brand new color choices. Perfect fit for your Fitbit One activity tracker and comfortable wearing experience.30 day money-back guarantee. Please note that the step count sensitivity of the tracker might be altered when worn on wrist depending on tightness. However, the trend of your daily activity will NOT be affected.