Reusable, eco-friendly linen coffee filter. Simply made with 100% linen fabric. It extracts the coffee's oils, which are absorbed by paper filters. Wet it before use to help it fit the dripper. You can enjoy both a light taste and a rich, deep flavor depending on the drip speed. After use, wash gently with water or hot water and hang to dry. If you are concerned about oil, wash with soap. Please understand that this is handmade by an amateur. By the way, I use it about twice a day for several months, and it still seems usable. The length of one side is 13cm. It can be used for a 4-5 cup dripper.