Yeah. unscrew the top, place the o ring on the lip, slide in a straight stem and then place the unscrewed section back on thru the top of the straight stem (whilst the straight stem is still inserted) then tighten the screw top back on to the main section and the o ring should push into place, then you can remove the straight stem and use whatever stem you like.
Ends up looking like this -
That's sort of the right procedure
to use on Solo. However, since the caps varied in thickness after the mod was developed, you have to fit them with newer units carefully especially with the ones with the thicker caps (newer, thicker cap on left):
Putting the cap on with too much tension on the ring can (and does) break the plastic tabs on the bottom where the four screws are. Guys really clamp down on the ring sometimes (taking pride in 'I can pick the unit up by the stem') causing this damage, folks should be made aware of that possibility I think. The idea is to keep bent stems from rotating under gravity. The ring holds the stem 'naturally' and the cap clamps the ring just tight enough to keep it from rotating. It's not 'to tighten up loose stems.
Generally you need a thinner cord ring (same major diameter, but 'one step thinner'. Or sand flats on them. You can also pinch the ring and shave a bit off the bulge with a razor blade so it doesn't add air restriction (the photo shows the notches on the inside surface of the ring, I later switched to putting them on the bottom (better grip while still allowing air past freely):
But all that is on
Solo. The vape in question here is
Air.......it's probably a mistake, the rings have no use on this vape?
OF