Available in several sizes, 3M Filtrete Air Purifiers are superior performing room air purifiers while still being very quiet, with stylish designs that fits beautifully in most any decor. The two Ultra Clean models are equipped with a unique filter life indicator that actually senses the particle accumulation of the filter based on current air quality in the room. The indicator takes the guesswork out of determining when it's time to change the filter. For the ultimate in quiet air filtration for a small bedroom or office, choose one of the two Ultra Quiet models, which are the quietest air purifiers available for comparable room sizes. Or, clean the air in your office with a 3M Office Air Cleaner.