18 X 20 X 1 Standard Pleated Air Filter FPR 5 (3-Pack) Protects against lint pollen pet dander and dust mites Rated MERV 8 capturing particles as small as 3 micrometers Set of 3 filters will last 9 months by replacing every 3 months The HDX Dust and Pollen is made of wire-backed pleated media and provides up to 90-days of protection making it an ideal upgrade from standard spun glass furnace filters. These filters protect against many airborne contaminants including those that can irritate seasonal allergies and cause unhealthy respiratory environments. The HDX Dust and Pollen is easy to replace making change-outs quick and keeping indoor air quality at its optimal level. Contaminants Captured: Dust/Lint Pollen Longevity (months): 3 : 90-Day Air Filter Type: Non-Electrostatic Filter Performance Rating (FPR): 4-5 - Good Pack Size: 3 Filter Frame Material: Cardboard Air Filter Features: Pleated Filter Material: Fabric MERV Rating (Minimum Efficiency Reporting Value): MERV 8 : 30 Days Air Filter Width (in.): 18 Air Filter Size: 18x20 Actual Product Width (in.): 17.75 Air Filter Depth (in.): 3 Actual Product Height (in.): 19.75 Actual Product Depth (in.): 2.75 Air Filter Height (in.): 20.