• A replaceable device designed to remove dust, pollen or other foreign matter from the air passing through it
• The removal of particles is accomplished by porous fibrous or shredded material (metallic or nonmetallic) which is loosely woven or matted and confined in a frame or retained between perforated sheets of firmer material
• It is designed to fit into air conditioners, ventilation systems and hot air furnaces
• It may have facilities for radio frequency/electromagnetic interference shielding
• The filter may be cleaned by the use of compressed air, blown through the filter element, or by using water and a suitable detergent for cleaning purposes which would extend the life of the filter