This is a printable sideprotectors for the JBL Charge 4 Speaker. It prevents damage of the speakers at the side. This might be a useful addon if you transport the Charge 4 in a backpack with other stuff, that might pinch the speakers.
Both sidecovers are hold together by flexible filament, which got welded together with a lighter. Of course you can also use a rubberband or so. Both solutions make the sidecovers be easily removable.
For printing, I used Z-Flex. Anyhow, flexible material has the advantage of not rattling when having much bass in the music.