Quoted from dmacy:Comet rings. Color matched to the cap colors. These are the ones you need to notch inside the cap for the leads and hot glue inside.
These:
https://www.cometpinball.com/products/pop-bumper-rings
I’ve heard that if you are not very careful with those they will short out and blow? I cant remember what thread I read that in. I had my eye on the bright mods rings that snap right into the light socket. Seems cleaner and easier.