Nu-Aera Air Filter&trade;, 14"x24"x1", 4-Pack Provides edge-to-edge antimicrobial protection Incorporates Sporax, anti-microbial agent, developed by Abbott Laboratories, to guard against the filter from becoming a breeding ground for bacteria, fungi, mold and mildew. Sporax is approved by the EPA, FDA & USDA Advanced design guarantees 100% of the air passes through the filter to deliver optimal performance Sticky ''tackifier'', on the back of the filter is used to retain the smallest of particles including pollen, dust and animal dander Lasts up to 3 months