Streamlined Air Outlet: Ensures effective air circulation. 3-Speed Fan: Support smart mode with integrated air quality sensor and different purification needs. 4-In-1 Efficiency Air Filter: Pre-Filter, Activated Carbon Layer, High-Efficiency Silver Ion Air Filter, Anion technology Eliminate >99.9% of coronavirus (COVID-19) in within seconds 4-In-1 Efficiency Air Filter Pre-Filter to intercept large particles, dust and hair Activated Carbon Layer to remove odor, formaldehyde and TVOC High-Efficiency Silver Ion Air Filter to eliminate bacteria, virus, and remove fine particles (PM 0.3) Anion technology: sterilization and purification