The Bendix two-way (TW) series valves are manually operated, non-graduating, on-off valves. They are extensively used in air systems to control nonmodulating air controlled devices. They may be lever or button operated, direct or remote control. The Bendix+ TW-3 valve is lever operated, either direct or remote and has a larger body and capacity. Some versions have a heavy inlet valve spring making them suitable for vacuum control.