Carbon Pre-Filter 2-pack for BlueAir 200/300 Hepa Filter 2-Pack of Activated Carbon Pre-Filters Designed to fit the BlueAir 200/300 Particle Filter Saves the life of the hepa filter by removing large particals before they clog the hepa filter Removes unpleasent odors from the air Each filter Measures 17.5"x14"x.2" and are made in the USA from CFS