This Membrane Solutions MS18 air purifier is the best treatment option for allergy sufferers, and comfortable air 24/7 for rooms up to 825 sq ft. our air purifier (23.00″ x 11.90″ x 23.60″) has 3 stages filter: H13 True HEPA + Activated Carbon + Ion Capcher) and a washable pre-filter that captures and reduces up to 99.97% of particles as small as 0.3 microns in the air, including dust, pet dander, pet hair, pollen, cigarette smoke, odors, VOC and more. With a 2/4/8-hour timer, sleep mode is as low as 29dB noise without disturbing your sweet sleep. Stay clean air in your home with our Membrane Solutions MS18 air purifier.