Considering that almost all camera lens filters are made out of metal, you basically only have to protect the glass. Using these caps will safe you a lot of the bulk that most other filter cases create.

I made this printable swirly bokeh filter that gives you the swirly bokeh look from old vintage lenses. The filter thread and cutout sizes are customizable to make them fit your own DSLR/Mirrorless lens. #Newmodel