Odor Control: Pre-filter included, our item will soak up and eliminate the undesirable and ill-smelling odors of bathroom, kitchen, drying rooms to keep your place clean while bring you cleaner air. Reversible Flange & Base: The flange and bottom can be removed to reverse the charcoal canister, making the filter body could be flipped upside-down for reversable smell filtration and also extend the service life. High Efficiency: Machine packed carbon enables 99.8% filtered air flow. Inner and outer mesh provides 53% open area allowing increased air flow, easy compact with the Inline Fan(not included). Absorbent Carbon Filter: 4 inch carbon filter, 1050+ IAV Australian virgin charcoal bed. Optional Size & Top Customer service: 4" & 6" for your better choice, and the item has better absorption and effective. If our product does not meet or exceed your expectations, please contact us at any time. One-year warranty: Our warranty is ironclad and truly hassle free.