This 55-110 CFM 4 in. fan/filter combo removes odor and purifies air by sucking the air in the room through the carbon filter and expelling it out of the room. When integrated into your exhaust system, all the air that leaves your growing environment it totally and completely scrubbed before exiting. (Rooms 8 x 8 and Under). To use attach to a fan for exhausting and you have an instant neutralizing odor eater.