Single Cylinder - twin valves, why?

[O-ring]

Handy for stuff like this..

 

[GF99/99]

Ok - probably a silly question, I have been looking at cylinders for sale and have come across quite a few single tanks advertised with twin valves fitted. What if anything is the benefit of twin valves and why would you do it on a single tank other than redundancy?

Cheers P

Do you have a picture?

The wording is a little strange, at first I would think this is refereeing to H or Y valve as others have explained. But one could also assume that "twin valves fitted" could also mean just that. Twin valves on single tanks as this is super common as well. This is how "sidemount" valves are made. It is simply just a manifold split and plugs put in the ends.

So this would be the other reason why people put twin valves on single tanks.

 

[DAJ]

The OP probably figured it out 10 years ago…