Cat® Mixing Flaps are used in an HVAC system in which the air passes through ducts or pipes. A flap is used to open or close, either fully or partially, certain portions of the duct in order to control the direction of airflow. A flap actuator, also called a damper, is simply an electrical machine that moves the flap. Cat service parts offer simple repair and replacement of system components in Cat heavy-duty equipment.Application:Consult your owner’s manual or contact your local Cat Dealer for more information.