"Pit Pocket" Create a cover with gauze to plug directly into your handmade or non-woven mask. Simply insert the high-performance filter "Pit Filter" inside it and place between your face and your handmade mask or non-woven mask and you can use it comfortably without direct contact with your mouth. Furthermore, there is a wire in the part that touches the nose, so it fits securely without slipping. The cover uses gauze, so it can be washed repeatedly and economical!! Pit Filter Sheet / Micro 0.1 compatible non-woven filter reduces intrusion of spray viruses, PM2.5, pollen, dust, and other particles by 99%. (Subtle particle collection (filtration) efficiency tested: Kaken Test performed by the General Foundation) The sheet is 3.9 x 33.1 inches (10 x 84 cm) so please cut it before use. (Pit Pocket size 12 sheets approx. 3 months supply); Wash once a day for a week, making it economical. The cover is made with gauze and the filter is inserted into it, so you can cut out 99% of intrusion from spray viruses, PM2.5, pollen, dust, etc. When washing, place it in a laundry net and always dry it in the shade. Leave it wet to avoid smells and mold, so please avoid it when wet. Do not use chlorine chemicals as they may cause discoloration. Filter absorbs fine dust and other particles when handling. We will try our best to do it, but it is not possible to completely avoid the contact of fine dust and lint. Thank you for your understanding. Due to the nature of the filter, there may be some pilling on it, but please use it without removing it. Please wash it gently with water. Do not use detergents or other similar products.