My friend gave me Rose V3, but he lost airflow ring. Of course you can not
buy original spare ring ? So I made a new one with one idea in my mind, basically RoseV3 is not mtl so I made AF ring with just one hole 2mm. And there is one other idea, why not bras ring like a spring. So I cut and open ring with hole, and now you can easily turn around AF ring and it did not need O-ring or wire. It clings to the atty body
here it is simple as simple can it be

Solid Brass Hex Nuts 3/4” NPT Female
Thread
and simple proxxon drill with few attachment's..
Hope you like idea and job..