The gas bottle without valve guard reminds me of Laos. I have yet to find a valve protector over here - scary...

Question:
How would you be able to know for certain what the contents of a gas bottle is e.g. N2, or O2, if you don't trust the sprayed writing on the outside? Could even be the wrong valves for all one knows.

I literally go through my prayer list every time I use a new bottle of OFN to purge a system - in case is perchance is O2!!!