Adaptors an connectors gas bottle

[JoseJu]

Hello everyone,
I have an enquiry about connectors I have in my motorhome.
The red connector has a big nut than the silver, why?

Also, the green connector is different and I have not clue what is it working for, any idea?

Thank you for any help.

Jose

 

[funflair]

Different regulators so different nuts but the bottle connection has to be the same.

 

[M-J]

Is the green one a safety cut off valve?

 

[JoseJu]

Is the green one a safety cut off valve?

Yes, I think. It is Truma on top