Roomba I4 Air Filter

To use, Print out inner and outer shells, cut a sheet of cheap home central air filter material slightly larger than the outer shell. Trim the corners of the newly cut sheet of filter so it resembles a fat cross shape and lightly glue to inner shell then push the inner shell into the outer shell. Use high temp hot glue to attach a pipe cleaner or thin foam to act as a gasket on the face of the filter that inserts into the Roomba. Disclaimer - I have not tested this filter long term and made to hold me off until my low-cost filters came in. filters from Roomba are pretty pricey. However, it cleaned the air very well and did not cause any issues.