Garmin Vivosmart HR restart, reset and band replacement - YouTube
Support: Battery Replacement on a vívofit® jr. 2 - YouTube
Amazon.com: Garmin vivofit jr. 3, Fitness Tracker for Kids, Includes Interactive App Experience, Swim-Friendly, Up To 1-year Battery Life, Blue Stars : Sports & Outdoors
vívofit jr. 3 - Replacing the Battery
Replacing the Batteries
vívofit jr. 3 - Replacing the Battery
Amazon.com: QGHXO Band for Garmin Vivofit 4, Soft Silicone Replacement Watch Band Strap for Garmin Vivofit 4 Activity Tracker, Small, Large, Ten Colors (10PCS Bands, Small) : Electronics