Advanced 4-stage filtration system: Real air purifier, a combination of pre-filter, real filter, honeycomb activated carbon filter and sterilization cotton, which works efficiently and smoothly, reducing 99.97% of airborne particles as small as 0.3 microns. These include dust, pollen, smoke, odors, mold spores and pet dander. Suitable for any small or medium-sized room up to 20 square meters. Quiet: Low noise design for a comfortable hanging mode of up to 28 dB without disturbing the night. While you sleep, you will be pampered by the fresh, clean air. The air purifier is equipped with a night lamp that can be adjusted from low to high brightness depending on the desired sleeping environment. Can be turned off when the light is sensitive to light. Three speeds and auto-off timer: three fan speeds, sleep mode (