Fitbit is the world's best-known and most popular smart fitness tracker. The Fitbit app is built into the device and works in sync with it, so you can check your stats and progress wherever you are.

You can also track multiple users on one device and see their progress in real-time.

To make the most of your Fitbit experience, you can download the Low Battery Notifier for Fitbit app.

You can set the notification interval to fit your own schedule. If the app detects that the battery is low, it will notify you before it reaches the critical level. This way, you can be sure that you'll be alerted before the battery runs out.