air breather?

I seen this real small air filter It looks like a k&n filter but alot smaller.I think its called a breather or something like that.Does any one know where this goes and whats the purpose of it.

Thanks

It goes on where the oil cap is on the front valve cover.

It is used on Intercooled GTP's because many of the intercoolers block the stock PVC hole. So in other words really no use unless you intercool

Well,not intercooled yet.Thanks Ripn.BTW your car looks awsome lowered.I would love to do that to mine but I dont want to give up the ride quality.

IC, when I finally finish the car and build the Intercooler I have in paper since it has so little parts quantity hope it will be a lot easier to deal with and no need to cover the PVC valve. Breathers were used mostly on carburated cars where the oil vapors were "recycled" thru the carburator into the engine.