General description These 40 Electrostatic Filter Cotton Sheets measure 28 inches x 12 inches and utilize innovative electrostatic filter technology to effectively isolate particulate pollutants larger than 0.2 μm in the air. With a filtration efficiency of over 95% for 0.5 μm dust, these filters significantly improve air quality by capturing dust, pollen, bacteria, and other pollutants. They can extend the life of your air purifier's filter by more than double, reducing replacement costs. Technical specifications Dimensions: 28 inches x 12 inches (30x72 cm) Filtration efficiency: Over 95% for particles larger than 0.5 μm Wind resistance: 3.5 Pa at wind speed of 0.5 m/s Material: Fiber Color: White Package Contents: 40 x Electrostatic Filter Cotton Sheets Measurement allowed error: +/- 1-3 cm Compatibility and accessories Compatible with Mi Air Purifier 1/2/Plus Can be cut to size for air conditioners, windows, and electric fans Used in conjunction with HEPA filters to extend their