PC fan filter
thingiverse
these filters are designed to populate empty fan mounts. you have two sizes 120MM and 80MM fans, both with standard screw holes. i use napkin as a filter but you can use other materials.
Download Model from thingiverse
With this file you will be able to print PC fan filter with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on PC fan filter.