Naiture 10" x 10" Oversized Smooth Cast Iron Wall Register Old Victorian Style Duct opening size: 10" x 10" (11-1/8" x 11-1/8" Overall) Heavy cast-Iron with rustproof black powder coat finish for durability and reliability. Removable louvers. Louver control extends 3/4" H from vent which could control air flow easily by foot. Includes tension springs and all the necessary mounting hardware for securing into wall ducts. No screws required. To determine size needed, measure air duct opening rather than old register or grille.