This Oxygen Valve, used by the aircraft commander and cargo master, is the primary on/off selector for crew and passenger oxygen supply on the C-17.
![](https://essexindustries.com/wp-content/uploads/2016/01/On-Off-Oxygen-Valve-1.jpg)
This Oxygen Valve, used by the aircraft commander and cargo master, is the primary on/off selector for crew and passenger oxygen supply on the C-17.