The EZ-FLO Return Air Filter Grille is designed for wall or ceiling openings on central air system plenums for mounting an air filter. It is made of heavy-duty steel with a white powder-coated finish that resists flaking and rust for a longer-lasting performance. It fits a rough duct opening 10 inches wide by 10 inches long. It features slotted vanes that are non-adjustable and in a fixed position and a hinged panel with two latches for easy air filter replacements. Includes (4) screws for easy installation. This return air filter grille accepts most 10-inch by 10-inch air filters. It is important to check the duct opening size before purchasing a return air filter grille.