AIR QUALITY REMIND: Advanced sensor monitors the air quality, LED light shows the status of the air quality. POWERFUL HEPA FILTER: Unique 4-stage filtration is more powerful than other filtration: Pre-filter filter cloth HEPA filter activated carbon filter. H13 HEPA filter remove 99.97% of airborne particles down to 0.3 microns. QUICK PURIFY: Capable of delivering 141 CFM (240m³/h) of clean air, perfect for home, large room, bedroom, office, kitchen, baby room. 22dB ULTRA-QUIET: Always create a comfortable and fresh indoor environment for your work, sleep and study. Suitable for sound-sensitive people and light sleepers. FILTER REPLACEMENT INDICATOR- The filter replace indicator will flash red when it's time to change. We recommend replacing it every 6-8 months to ensure the best performance of the air purifier.