Blowsion billet fuel cap question

[Dalef10ods]

real simple I know but With the Blowsion billet fuel cap for me SXR. The inside of the cap has a rubber o-ring, and a black centre round rubber. Do I need both or just the outer?

Also I want to connect it to the chain so I don't loose it but there is no screw inside the cap, you hunk they would give you a screw for $60 bucks!!!!

 

[Shonuff]

I just use the flat black rubber gasket on mine. Don't worry about the chain. I have it on mine and that heavy bastard likes to scratch my nose when I take the cap off so you end up having to be VERY careful with it.

 

[Big Kahuna]

Wait, Who you bee?
@Shonuff