The Membrane Solutions MS18 Air Purifier is a 4-stage filtration system designed for large rooms up to 825 sq/ft. It removes 99.97% of particles as small as 0.3 microns and air pollution PM 2.5. The washable pre-filter captures hair, pet dander and fibers, while the blue silver ion filter neutralizes pollutants like dust, mold, and pollen. The H13 True HEPA filter captures smoke, mold, allergens, dust, and pollen, while the activated carbon filter removes bad smells from cigarette and pets and hazardous chemicals element (VOCs) such as formaldehyde. This air purifier is perfect for smokers, pet owners and allergic groups. It features 3 fan speeds, a washable pre-filter, night light, sleep mode, timer 2/4/8 hrs, and filter replacement indicator. The physical keys and timer make it easy to use, and it operates with a low noise level of 29dB. It is CARB-Certified and 100% Ozone-Free. The package includes 2x MS18 Air Purifier, 2x Filter Element (Pre-installed inside the air purifier), and 2x Operator Manual. The replacement filter is available in 1 Pack, 2 Pack, 3 Pack, 4 Pack, 5 Pack, 6 Pack, 8 Pack, and 10 Pack, with a filter service life of 6-8 months (depending on usage).