The AFB Silver MERV 8 furnace / air filter is the most commonly purchased replacement filter by AirFilterBuy. The AFB Silver filters pollen, mold, dust mites, and other particles that are up to the size of pudding mix that you might buy at the grocery store. We recommend the AFB Silver Merv 8 filter for basic home and residential use. It will protect your AC / furnace system, while offering adequate filtration to keep your home dust and pollen free. Whenever you are choosing an air filter, make sure that you compare the nominal and actual size of the furnace filter that you are replacing. In this case, the nominal size is 13x20x1 while the actual size is 12 7/8 x 19 7/8 x 3/4". Generally, the nominal size is rounded and in bigger print while the actual size is in smaller print and in parenthesis to the side. The AFB Silver MERV 8 filter is designed to last 3 months, or 3 times the average fiberglass filter. The filters ship directly from the manufacturer to your doorstep, allowing AFB the ability to offer a premium product at a reasonable price. Each quantity purchased is for a pack of 6 filters. Note that AFB filters come in AFB Bronze (Merv 6), AFB Silver (Merv 8), AFB Gold (Merv 11), and AFB Platinum (Merv 13). The most commonly used filter for home or business use is the AFB Silver (Merv 8). If you have pets or allergies we recommend the AFB Gold (Merv 11). If you have asthma or other respiratory illness, we recommend the Merv 13. AirFilterBuy: Breathe Better!