Up to 15 times more effective than spun glass on sub micron sized particlesSize: 18" x 20" x 1"About twice the surface area of flat panel filtersDesigned to provide allergy reliefMerv 8 low airflow resistance for better equipment operation and to help save energyHighlights: Up to 15 times more effective than spun glass on sub micron sized particles Size: 18" x 20" x 1" About twice the surface area of flat panel filters Designed to provide allergy relief Merv 8 low airflow resistance for better equipment operation and to help save energy Lasts up to 90 days Captures particles as small as 5 microns in diameter- pet dander, mold spores, ragweed, pollen, dust mites and debris