Review on KOIOS H13 HEPA Air Purifier for Home, Small Room, Office Desk - Removes Pet Hair, Dander, Smoke, Pollen - 100% Ozone Free - Night Light by David Ross

I wish I had done more research on CFM and CADR. This little device purifies the air at a painfully slow rate of 20 cubic feet per minute. This may be enough for light work in a VERY SMALL room (closet), but do the math first. (To remove pipe smoke from a well-ventilated 165 square foot room, I need at least 220 cfm!) I also noticed that the filter image shows the pre-filter, HEPA, and "charcoal" layers as three separate layers with a charcoal layer . has multiple honeycomb design. In fact, there is only one black pre-filter over HEPA. Maybe the pre-filter is bricked up with charcoal, but I doubt it. Hope that helps.