Rubberized feet serve as a cover for the screws.
If you open this, the whole thing looks like in the photo.
Changing the battery is therefore not readily possible, but not impossible.
The X3 reduces the volume automatically, and the battery drops below a certain value.
Would replacing the Battierien better resolved, I would forgive 5/5.
But you do not give out more than 100 euros for disposable speakers.