Philips AC4372 Air Purifier with professional filtration system , smart sensor gives accurate feedback on indoor air quality. Turbo made cleans air instantly at the highest speed. Product turns down fan speed and noise level in silent mode, all lights on products are off. 6 settings to give you ample choice in fan speed. Healthy air protect alert gives you a timely warning when to replace the filter. 6 settings to give you ample choice in fan speed. Light sensor automatically turns off all lights at night. Auto mode ensures hassle-free functioning. 1/4/8 hour easy-to-set timer Professional Filtration system effectively filters out harmful gases and pollutants with a size of >0.02 micron. Child lock prevents unintended changes in settings.