【SMART SENSOR:】 Our air purifier equips with an air quality sensor for real-time displays air state on the screen in green/yellow/red ring. Meanwhile, on auto mode, the fan speed will adjust automatically depending on the air quality. In addition, features a temp/humidity sensor to check the real-time temp/humidity, which helps you make corresponding adjustments for need. 【TRUE HEPA AIR PURIFIER:】Breathe fresher air with Biange air cleaner which could filter 99.97% of particles as small as 0.3 microns. Ozone-free and 3-stages design, includes fine preliminary filter, true HEPA filter and activated carbon pre-filter. It traps large particles such as hair, pets dander, captures small particles, such as smoke, dust, pollen, and removes odors from pets, smoke, cooking fumes, VOCs .etc. 【WIDE PURIFICATION SPACE:】 CADR rated up to 180 m³/h, refresh air up to 269 sq.ft in 20 mins (3x/hr). Biange air purifiers for home large room suited for medium rooms like living rooms, bedrooms, kitchens, study, or dorms. 【QUIET&AUTO:】 Our HEPA air purifier supports sleep and auto mode. In sleep mode, screen turns off, fan speed reduces, working at a whisper-quiet 25db will not disturb your sleep. The portable air cleaner has three fan speeds, the first gear which is the most frequently used is 32db, still not interfere with your normal work or study. In auto mode, the purifier will adjust the fan speed according to the air quality. 【TIMER&CHILD LOCK&FILTER REMINDER:】 Function with timer, which allows the home air purifier to shut down after setting of 2/4/8 hours.