Estilo EST146B Set of 8 Compost Pail Filters, 4 Round and 4 Square, Black Compost Bin Charcoal Replacement Filters. Package includes 8 filters. 4 round and 4 square. Compatible with most stainless steel compost pails. Round filter measures 6.5 inch diameter. Square filter measures 4.75 inch. Easy to replace. Filter contain charcoal - please do not rinse.