Intake gasket, what are these things for?

Part Number: felpro 90109

http://shop.advanceautoparts.com/we...?searchTerm=intake+manifold+gasket#fragment-4


There are what look like 4 small O rings with this gasket set. where do they go and what are they for?

I'll be picking it up tomorrow when its in but, curiosity got the best of me and I just had to ask about them.