The Bendix two-way (TW) series valves are manually operated, non-graduating, on-off valves. The Bendix® TW-12™ is extensively used in hydraulic braking systems to control devices that are responsible for the application and release of the parking brakes. Note: The TW-12™ control valve can also be used in air brake system applications. The most common configuration of the TW-12™ control valve uses a levered cam that is manually, remote controlled. A dash mounted lever or button may be connected to the aluminum lever cam via Bowden cable control or connected directly to the transmission selector.