Gas bottle connection valves

[Pappabank]

Hi folks can anybody help me with the black button/screw thing on gas bottle regulator
what does it do ?should it be open or closed ?any info/help please
we have a 2011 swift 686 escape on fiat ducatto

 

[SandraL]

Theres many types of gas bottles, any chance of a photo?

 

[andy63]

Hi folks can anybody help me with the black button/screw thing on gas bottle regulator
what does it do ?should it be open or closed ?any info/help please
we have a 2011 swift 686 escape on fiat ducatto

If you are on about the regulator it will be a cover for a test gauge..
Andy