This is a single, unopened pack of Toyo Aluminum "Patto Haru Dake" Dust Filter for ventilation fans, approximately 30cm x 30cm, containing 3 sheets. I purchased a set of two from Amazon in December 2025. One has been used, so I will send the remaining unopened one. Please refer to the images (photos 3-5). I hope to give this to someone who needs it. Thank you. Product: Toyo Aluminum "Patto Haru Dake" Dust Filter for ventilation fans, approximately 30cm x 30cm, 3 sheets x 2 sets, with a start date sticker from felvita.