In addition to catching particles such as pollen, dust, pet dander, hair and mold spores with MERV 8 efficiency, Colorfil furnace + air conditioning filters capture and neutralize odors and chemicals at a molecular level, binding them without releasing any harmful byproducts. Colorfil was originally built for NASA and designed to meet rigorous performance and safety requirements to help protect astronauts and spacecraft. Now available for everyday use, our filters are recommended for homes and offices to help create clean, fresh, and welcoming living spaces for both humans and pets. Colorfil is the only filter that shows you when it’s working, changing color from pink to yellow as it captures and neutralizes odors in your air! When selecting an air filter, make sure to compare the nominal and actual size of the furnace filter that you are replacing. The nominal size is typically in larger print and rounded to whole numbers, while the actual or exact size is in smaller print or in parenthesis. Exact size may also be easily identified with the help of a ruler or measuring tape.