Quietly clean air. I love the colored light that surrounds the Power button. My bed room is at the end of a much-traveled hallway. I like to leave my door open so I stay connected to the rest is of my active family and their dog. But I bought the Alen so I could breath clean air. When the light around the Power button changes to red, it's time for me to close the door. I am breathing so much better because the Alen cleans the air and gives me a colored status.