Naiture 2-1/4" x 10" Brass Wall Register Honeycomb Style Antique Brass Finish Duct opening size: 2-1/4" x 10"(3-1/4" x 11-1/8"Overall) Made of heavy-duty solid cast brass for durability. Finished with a durable antique brass powder coat finish to resist rust. Louver control extends 3/8" H from vent which could control air flow easily by foot. Includes set of four springs for securing into wall. All the necessary mounting hardware included. To determine size needed, measure air duct opening rather than old register or grille.