This is the replacement damper bracket for your microwave. It is made of plastic and is approximately 11 inches wide and 3 inches long. The damper bracket attaches to the outer cabinet and directs airflow through the vent duct. The main reason you would replace the damper bracket is if it is damaged and will not hold the damper in place properly. This part is sold individually and is a genuine OEM part sourced directly from the manufacturer.