Broan MD10TU Motorized Universal Make-Up Air Damper with Pressure Sensor Kit, 10" Interlocked make-up air dampers provide make-up air when called for to keep the home comfortable by allowing the range hood to operate at optimum levels Direct wire design works with select BROAN range hoods to balance indoor air pressure by providing interlocked make-up air; damper opens automatically when fans are activated Slave dampers (MD6S, MD8S or MD10S) are interlocked to the main automatic or universal make-up air damper and open in unison for synchronized operation Interlocked make-up air systems avoid wasted energy associated with barometric solutions and do not let unwanted air into the home during heating or cooling activities so air pressure is equalized for a well-balanced environment