To change the batteries:

1. Remove the siren from the Smart Bracket.
2. Turn off the indoor siren .
3. Open the four screws on the back.
   
4. Now remove the cover (back) of the indoor siren.
   
5. Now replace the two batteries with new ones of type CR123A. Pay attention to the polarity PLUS and MINUS.
   

   NEVER use used or defective batteries.

6. Replace the back cover of the siren and tighten the screws.
7. Turn the siren back on and check the battery status via the APP.
   

   The battery status is not updated immediately, but the next time the devices are polled (every 36 seconds by default).