The return air filter grille measures 31-11/16 inch x 11-11/16 inch with a duct opening of 30 inch x 10 inch Constructed of heavy-duty steel that provides strength and durability Features a powder-coated white finish that resists flaking, scratching, and fading 6 vent rows Designed to improve air ventilation in HVAC systems Compatible with 30 inch x 10 inch filters Mounting hardware is not included with this product