Compost keeper filter refills for #83， #93， #93R and #93EB. Change the filter approximately every 6 months， depending on use. That time can be affected by heat and humidity in your area. Let food cool down before putting it into the composter. Do not put hot or warm product into composter. Moisture from warm product can decrease the time for changing the filter. Each filter is 5.625 in diameter and is made of PET (Polyethylene Terephthalate)， 5% Charcoal， 95% PET Acrylate. The filter should never get wet. Do not wash and reuse the filter. The charcoal in the filter absorbs the odors and once it has fully absorbed to its maximum， discard filter. To Replace Filter: just pull old filter out and toss. Inside replacement packet are two filters. Just place one filter in the lid.