Fluted, designed to eliminate overflow. 100% pure virgin fiber. Screens out bitter oils and sediments for robust flavor coffee or tea. Manufactured and tested to meet all FDA requirements; and to assure purity, uniformity and consistency. Continuously che cked for proper porosity, flow rate and proper structure. Box and filters 100% biodegradable. For Bunn B8 and GR home brewers; fits most other automatic drip coffee brewers for the home.