Nordic Pure 16x25x5 1/4 Goodman Replacement MERV 8 air filters are unique because of the actual size of the filter compared to the nominal size. Typically, a 5” filter is actually a fraction of an inch smaller, while these filters are larger at 5 1/4”. Other commonly known systems that use this filter size are Amana, Five Seasons, and Totaline. Please note that these name brands are not a comprehensive list; you may have a different system with the same measurements, so always measure your ac filter’s housing to ensure you order the proper fit. 5” Goodman 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. 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” 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 3-6 months to maintain maximum efficiency and economy.