HAK PNEUMATIC has a complete line of pneumatic Shuttle valve
Shuttle valves are designed to direct flow of fluid from two sources. A simple sealing element is designed and installed to move freely within the shuttle valve. When pressurized fluid enters the shuttle valve chamber the pressure of this fluid forces the shuttle sealing element to the opposite end of the chamber.
When landed, the sealing element provides a shut off of the chamber from the second flow source, but allows flow through the middle opening The shuttle valve prevents backflow from one flow source to the other flow source