I have used these quick connectors for some years now, with no problems, just remember to push them all the way or they can block the flow.
If you want to use it on several bikes, be aware that even if they look the same, different makes are not compatible.
The outside diameter is 9mm, so an 8 mm tube is neccessary and it will go on the tank as well.
_________________
Poul
"If Life Gets Boring, Risk It!"
MC21SE, KISS box
MC21SP, HRC box, racing loom