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™ Stamped Face Return Air Grille, 1-Way, Series: 173, 20 in W x 24 in H x 1/4 in THK, 694 to 1618 cfm, 356 sq-in, 1/3 in Blade Spacing, Steel, White Powder Coated