Naiture 6" x 6" Louvered Wall Register, Return Vent Cover Grille, Unfinished Cherry Duct opening size: 6" x 6" (8" x 8" Overall) Made of high-quality 1/2" thick unfinished cherry wood. Easy installation. Includes mounting holes on back of the return but no mounting hardwares. This Wood Wall Return features bold lines that are a perfect accent to any home. This return has several size options. To determine size needed, measure air duct opening rather than old register or grille.