Amazon.com: Garmin vivofit jr. 3, Fitness Tracker for Kids, Includes Interactive App Experience, Swim-Friendly, Up To 1-year Battery Life, Digi Camo : Electronics
HQRP 4-Pack Battery for Garmin Vivofit Vivofit-2 Activity Tracker Fitness Training Computer (2 Batteries for Training Computer + 2 Batteries for Heart-Rate Monitor) 010-01225-00 - Walmart.com
Garmin VivoFit 4 - Battery Replacement - YouTube
Replacing the batteries in a Garmin Vivofit 4 - YouTube