Nordic Pure 16x25x5 Air Bear Replacement 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 8 rated filters are made of electrostatically charged synthetic materials that attract and capture most airborne particulates in your home. Each time air passes through a Nordic Pure pleated filter, lint, household dust, pollen, dust mites, mold spores and other contaminants are removed. Our treated synthetic filter media prevents the growth of bacteria or mold, resulting in a much healthier living space. MERV 8 air filters are comparable to air filters with the MPR rating of 600-800, FPR rating of Green, or APR rating of Gold. Particles in indoor air are measured in microns; for scale, a human hair is about 70 microns wide. Each Nordic Pure 5” MERV 8 air filter captures up to 85% of airborne particles as small as 3.0-10.0 microns. 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 30-90 days to maintain maximum efficiency and economy.