Check the listing for details. 15x20 DustLok 3-ply Panel Filter MERV 9 (4-Pack). Condition: New. Listed at 56.49 USD. MERV 9 Efficiency Rating > 90% Dust Arrestance Efficiency per ASHRAE 52.2 3-Ply Graduated Density 100% Synthetic Media True Depth Loading for Optimum Dust Holding Capacity Up to Four Times the Service Life of Common Pleated Filters Spor-Ax Antimicrobial Biocide An Outstanding Choice for Allergy Sufferers Effectively Controls... Mold Spores Mildew Algae Fungi Dust Mite Debris Pollen Pet Dander Household Dust Particles That Can Carry Bacteria & Viruses Dustlok Tackifier Makes Filter Changes Clean - Dirt Stays in the Filter! Prevents Sifting and Migration of Finer Particles During On/Off Cycles Self-Sealing Perimeter Design Zero Dirty Air By-Pass - Dirt Cannot Go Around or Between Filter 100% Filtering Area - Airborne Contaminants and Particles MUST Enter the Filter Rugged 9 Gauge Internal Wire Frame The Best Choice for High Humidity Environments & Climates No Moisture Damage - Filter Holds Together Even When Wet Will Not Bend, Buckle, Rack or Collapse Stands Up to Rough Handling & Difficult Service Conditions