the success and design of the oreck truman cell is the secret to the amazing performance of the proshieldplus. a powerful fan moves the air through oreck's patented truman cell, which electrostatically charges many dust particles, pet dander, pollen and other allergens, pulling them out of the air that passes through the filter like a magnet. and for odors, including tobacco smoke, cooking, and pet odors, oreck's incredible innovation, the helios shield, continually breaks down and reduces the odors as they pass through it releasing fresher cleaner air. as david oreck says, you have to move the air to clean the air, and that's exactly what it's doing. specifically, i wanted an air purifier because my daughter started, uh, to foster homeless little kittens and puppies. uh, they have a certain odor that goes with them, it's not necessarily pleasant. uh, when we got the proshield plus air purifier, i had no idea the difference it would make. i was so happy. i knew it would make some difference, but i can't imagine not having one now. the bottom line is, you've got to move the air to clean th