Nordic Pure 16x25x5 Air Bear Replacement MERV 8 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 8 Pleated Plus Carbon 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, mold spores, and unwanted odors 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” 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 the inside and outside conditions in which you live and work. We recommend that you change your air filter every 3-6 months to maintain maximum efficiency and economy.