What is this oring from the gasket kit?

[Justin35ll]

It's a small oring looks like the 4 that are used on the lower injector seal.Part number 16618-10V10All I could find it this

The 16618-10V10 is the rubber donut that the fuel rail sits in to seal against the intake manifold. Again, this is on the SR20DET motor with side feed injectors.

I don't get it.. isn't the only way the fuel rail sits againts the manifold is by the 4 injector holes? I originally thought this was maybe a new gasket for the FPR on the fuel rail.

[david200095367]

it has to be for the fpr when you unbolt it there you will see a small oring.