Arctic air Ultra replacement filters are made from a sponge material. No more wasteful paper filters! The filters are washable and reusable. It is recommended to replace the filter every 3-6 months for best use. For use with Arctic air Ultra (not included). how to replace filter: use the filter drawer tab to pull out the filter drawer & remove filter. Place filter in drawer in marked location, and close filter drawer. For best results: lightly pre-soak new filter under cold, running water. For even more cooling power, place a wet filter in the freezer until frozen.