This electrostatic furnace filter and air conditioning filter is made of 1 layer of specially designed tubular electrostatic filter media, 2 layers of fine mesh electrostatic filter material and 3 layers of extra heavy net electrostatic filter fabric. It contains over 10 times more electrostatic filter material than other electrostatic furnace filters and air conditioning filters. The Polypropylene filter media in this filter, and its the polypropylene that gives electrostatic filters their particulate arresting properties, is unique to Good Filter Company and is specially designed to create a slight turbulence in the air as it passes though for greater cleaning efficiency . This is a permanent, washable electrostatic furnace filter and air conditioning filter that is sturdy, efficient and easy to clean. It is used mainly in residential heating and air conditioning applications as the primary air filter where it dramatically reduces dust, pollen and other pollutants, but also performs most excellently in commercial and industrial applications where undesired particulates are a problem.. This is the best electrostatic furnace filter and air conditioning air filter we have ever seen. No one else makes an electrostatic air filter like this one! This electrostatic furnace filter and air conditioning filter cleans completely at each washing because It contains no polyester or foam filler to retain pollutants. The Good Filer Company "Turbo Trap" electrostatic air filter for furnaces and air conditioning systems is available in standard and custom sizes. Our 2" electrostatic air filters with any dimension larger than 20 x 25 may have a center brace for added strength, another Good Filter Company quality addition not found on other electrostatic air filters.