Composite Filter Performance: Combining pre-filter, HEPA high-efficiency filter layer and activated carbon layer can tackle 99. 98% of airborne particles as small as 0. 25 μm, improve indoor air. Ensure Deep Sleep: With a noise level of 25 dB for a restful and soothing indoor environment, you can leave it running by setting working time for 1, 2, 4, 8 hours at night without disturbing noise, helping you sleep deeply. 4 Adjustable Speeds: Air purifiers for bedroom allows you to choose a suitable speed from low, medium, high and sleep mode, based on your different purification needs for optimal performance. Easy to Change Filters: Filter change indicator remind you of changing filters in time. The filters can be changed easily and it is recommended to be replaced every 6 months. It also may need to be replaced sooner or later depending on the frequency of use and the air quality in your area. Tips: please remove the plastic bag of the filter before the first use. Safe And Reliable: The air purifier has undergone rigorous quality testing and meets stringent requirements. Have FCC certification, ETL certification and CARB certification. Built-in child safety lock, do not worry about the child’s curiosity operation. Allows all your families members to breathe pure air and live happily.