With filter cotton, it can prolong the life of the filterCompatible model:For Xiaomi air purifier 4 Lite Product features: How well the filter works depends on its ability to clean and aerodynamic design. Our brand new Xiaomi filter cleaner (antibacterial version) can effectively absorb PM2.5 particles, dust mites. Coated with a special antibacterial layer, it can kill bacteria. Activated carbon can eliminate pollutants in the air. Our app will remind you of the need to replace the filter. Main features: • Effectively eliminates bacteria, dust mites, PM2.5 particles in the air• With Special antibacterial layer, it can effectively kill bacteria• Four-fold cleaning effect with shiny absorbency• Suitable for Xiaomi Mi cleaner, Xiaomi Mi 2 cleaner, Xiaomi Mi pro cleaner• We suggest to replace the filter every 3 - 6 months