Special Features:

The downstream side of the filter shall have the word downstream printed on it with letters at least one inch high

Properties:

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, hot air furnaces, and electrical and electronic cabinets or housings. 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.