Brand new, unopened. 3 packs. This is a filter to prevent the ventilation slot (air vent) installed on window sashes from getting dirty. It catches allergens such as pollen q(^-^q) Size: Approximately 80cm x 7.5cm Quantity: 4 sheets (1 sheet) Material: Anti-allergen processed non-woven fabric ● Because it is an anti-allergen processed filter, it removes captured allergens. ● It is an adhesive type filter, so it can be easily installed like a sticker. ● It can be cut with scissors to fit the size of the air vent. ● It has a replacement notification sign that appears when the filter gets dirty (it may not appear depending on the airflow)