The Bendix® TCS-9000™ control brake valve is normally used to operate the trailer brakes independently of the tractor brakes. It may be used, however, wherever a hand controlled pressure graduation function is desired. The TCS-9000™ valve is handle operated and is designed for dash or panel mounting. It is not designed for use as a parking brake control and should never be used to hold the brakes applied when the operator leaves the vehicle.