What size o ring for a Midland diver 5 litre air gun cylinder, the larger one that fits into the neck.

[Stingray003]

Hi There.
I went to have my cylinder filled yesterday, and when I went to fill it today it was venting air.
The whip has a oring, but the larger ‘screw in fitting which the whip screws to appears to be missing’ it may have fallen out during the filling process.
I understand it’s a pressure fitting, and there is a recess but no oring.
Can anyone tell me which size oring is required.
Thank you.

 

[Owain]

You could call Midland Diving. Best chance of getting the right part

 

[GrahamHenderson]

. the larger ‘screw in fitting' which the whip screws to ...

G5/8 adapter

 

[Fatbob 59]

BS112 is the size you need

 

[Stingray003]

Thanks a lot
I’ve looked this up and it’s not that clear, could someone be kind enough to post a link to it or similar.
Thank you.

 

[Stingray003]

Is this them?

https://share.google/ftnhdjTf3Bx3g0Qhe

 

[Stingray003]

All sorted thank you.
I called Midland diving who were very helpful, and said they will send me one out to replace it.
They were very helpful.