Clean Air Distributing 2572 Replacement Filters for 1-Gallon Compost Pail 2552, 2-Pack Replacement Filters - for the 1-gallon stainless steel compost pail Each Pack includes two set - 2 Round: 6 3/8-Inches 2 Square: 4 5/8-Inch Charcoal filter - dual filters help keep odors from escaping Dual filtration - Contains two sets of filters Filters last up to 6-month