Nordic Pure 20x25x5 Air Bear Replacement MERV 10 Pleated Plus Carbon air filters measure an actual depth of 4 7/8”. This is a fraction of an inch larger than the traditional measurement, so always be sure to measure the actual size of your filter’s housing, as your system could also use this size. 5” Air Bear Replacement MERV 10 Pleated Plus Carbon air filters are made of a new dual material where the MERV rated material and carbon material are pleated together to form a formidable obstacle to dust and odors. Because the carbon is also pleated, there is 3 times as much odor-fighting capability in each filter. Each time air passes through a Nordic Pure pleated furnace filter, lint, household dust, pollen, dust mites, pet dander, baking flour, mold spores and other contaminants are removed. MERV 10 air filters are comparable to air filters with the MPR rating of 800-1000, FPR rating between Green and Red, and APR rating between Gold and Platinum. Particles in indoor air are measured in microns; for scale, a human hair is about 70 microns wide. Each Nordic Pure 5” MERV 10 air filter will capture more than 85% of 3.0-10.0 micron contaminants and up to 65% of 1.0-3.0 micron contaminants. The effective life of your air filter depends on both the inside and outside conditions in which you live. We recommend that you change your air filter every 3-6 months to maintain maximum efficiency and indoor air quality.