Trevi T-Fit 250 GPS Mode D'emploi page 13

6.In case of low battery and only one red grid is left
will occur to indicate that the voltage is low and recharging shall be
made promptly so as to avoid the loss of sports data due to automatic
shutdown caused by low battery.
7.The recharging duration is about 1.5 hours. It will go to the time
interface after the recharging is finished. If it is not used for a long time,
it shall be powered off and recharged once every month.
II. App download and connection
1. An App is required to connect the bracelet with a smart phone. You
can download relevant App by scanning one of the QR codes below.
Google Play App
2.Android users can download the App by searching "WearHealth"
through Google play;IOS users may download the APP by searching
"WearHealth" through App Store.The minimum requirements for smart
phone operating systems are Android 4.4 and IOS 8.2 and above.
IOS App
11
, a vibration
Android App