The Xiaomi Mi Air Purifier 4 has a 3-in-1 filtration system that eliminates 99.97% of 0.3μm particles. The high-quality activated carbon filter can purify the air and eliminate odors effectively to keep the air fresh and healthy. The PM2.5/PM10 dual-effect sensor displays the indoor air quality in real time and has a colour-coded light strip. The touch control buttons make it easy to adjust the purification settings. The top grille is screwed on and cannot be removed accidentally to protect infants.