The Wells N1-WL0171 HEPA/Carbon Filter Pack is manufactured to fit the M Series air purifiers only to provide clean air indoors. It has a two-part filter system a HEPA filter that removes 99, 97% of airborne particles including dust, allergens, and pollen as well as an activated carbon filter that traps smell, chemical vapor, and toxic gases. https://partsfe.com/n1-wl0171-wells-filter-hepacarbon-pk-as-m