The Aerostar 20x20x2 MERV 13 Pleated Air Filter (actual size: 19 1/2 x 19 1/2 x 1 3/4 inches) delivers high-efficiency filtration for cleaner, healthier indoor air. Designed for use in residential and commercial HVAC systems, this premium furnace and AC filter features a MERV 13 rating, comparable to MPR 1500-1900 and FPR 10, to capture particles as small as 0.3-1.0 microns. Not only that, but by buying in a multi-pack, you can rest assured that you always have a new filter on hand to make swapping filters out a breeze. These filters are compatible with most standard sized units but for the best fit, we recommend measuring your unit directly or obtaining the actual size from your current filter and to ensure you point the arrows in the direction of the unit for a seamless install.