This small plug-and-play unit connects into the factory wiring harness and allows the driver full control of the exhaust valve whenever they want. For too long enthusiasts have had to pay too much for command of their exhaust. We solve that issue. These controllers connect to the vacuum solenoid in the trunk to provide the driver control over their exhaust flap. Before purchasing please ensure your car has a VACUUM style exhaust valve. These DO NOT fit on electronic valves.