This ring is used to align the John Gold CM3 / CM4 controller.
In my case it was way back so I couldn't reach it with my hand.
You need two of these if you don't have the original ring anymore.
One for the inside and one for the outside.
The flat side of the ring is placed on the plastic of your car. The open side is faced to the controller or to the nut on the inside.
I advice to print it with ABS or PETG due high temperatures in your car.