This is "Dust-Catching Filter for Air Vents" from Toyo Aluminum. This product uses static electricity to capture fine particulate matter such as pollen and PM2.5 that enters from your room's air vents, keeping the air in your room clean. Manufacturer: Toyo Aluminum Ekco Products Co., Ltd. Application: For indoor air vents Features: Catches approximately 99% of pollen. Collects PM2.5 (fine particulate matter of 2.5µm or less) using static electricity. Confirmed to catch approximately 50% of particles in the 0.3µm to 0.5µm range. Can be installed on various types of air vents (round, square, square push type). Includes Velcro fasteners for easy installation. Size: Approximately 20cm x Approximately 20cm Contents: 2 filters Filter that catches 99% of PM2.5, 2 pieces, size 20cm x 20cm. - Product Name: Dust-Catching Filter PM2.5 - Quantity: 2 pieces - Size: 20cm x 20cm - Function: Catches 99% of PM2.5 Regular Price: 1500 yen Thank you for viewing.