(2) pieces Control & SAVE on energy bills with registers that let you control every room’s airflow with their open or shut slide operated louver assembly (damper box). Mounts to floors or ceilings, damper box cannot be locked in place. Polished & lacquered to prevent tarnishing their traditional scroll design & heavy cast brass are of superior quality workmanship. Mounting hardware not included. Overall 4 7/8 x 10 7/8.