Melitta Coffee Filters for Percolators, White (3.5-Inch Discs), 100-Count Filters (Pack of 24)
Specially designed to let coffee's full flavor through while trapping bitter grounds, oils, and sediment.  These filters are designed with a hole in the center to fit all  percolators with a 3.5 inch basket.  For best results, use regular or percolator grind coffee only.