LINKYO Activated Carbon Compost Bin Filter Refill Pack - Set of 3 Odor Absorbing Charcoal Filters (7.25" diameter) Set of 3 Round Filters: 7.25" diameter Absorbs and Traps Odors Inside the Compost Bin Leaving your Kitchen Smelling Fresh & Clean Fits Domed Lids for Most Standard-Sized Compost Bins (refer to image of lid) Made of Thick, High Quality Activated-Charcoal Replace Filters Every 2-3 Months; Do Not Rinse