TRUaire's Return Air Grilles simply returns air to the furnace where it is filtered and either cooled or heated and then recirculates through the air supply grilles. We offer a variety of removable face, stamped, fixed bar, and fixed-hinged return air grilles for your convenience. Each return air grille will offer it's own set of unique options. TRUaire™ Return Air Filter Grille, 1-Way Stamped Face, Series: 190RF, 24 in W x 24 in H x 1-3/4 in THK, 1-3/4 in Overall Depth, 776 to 1810 cfm, 395 sq-in, 55 deg Deflection, 1/2 in Blade Spacing, Steel, Powder Coated, Import