Flanders PrecisionAire 18 In. x 18 In. x 1 In. Grille MERV 4 Furnace Filter

Grille size air filters are specially made to fit Metal Aire brand return air grilles. Disposable panel type for furnace and central air systems. Metal grid on both sides gives extra strength. Filters pollen, pet dander, dust/lint, dust mites. Filters should be changed monthly in periods of high use. Filters are Class II, UL approved.