XRAY - Model racing cars

Hi,
I would like to ask about the setup of shocks. I've seen some team drivers setups, they do not use o-rings on shocks.
Is this o ring, which one is in the shock ? And what is the reason ? Is the oil doesn't flow out ?

Thanks

This means O-rings on the shock shaft outside the shock body to limit the uptravel of the shaft. There're always O-rings in the shock body to seal it.

The O ring on the outside of the shaft is sometimes used to limit uptravel. It's normally used to help prevent grip roll on high grip carpet.

Yes, because the O-ring prevents the chassis touching the ground during cornering, which is always bad but especially it's bad on carpet as said.

The o-ring work as an upstop. It prevents the chassis from bottoming out. For example if you use o-rings on the front shocks only wou will have less uptravel in the front which initially will make the car feel more reactive.

Ok to understand correctly, on team driver setup up sheets when they have the box checked off for no o-ring on the shock shaft that means they use no o-ring at all, or does it mean that they build the shock with the o-ring inside the shock body?

Ok I understand. Thanks for everyone.