My original valve is leaking and I ordered a replacement. The original valve has an "in" and "out" designation, however the replacement from fastlane shown here: http://img.eautopartscatalog.com/live/R302011893.JPG does not have this designation, but rather two different colors of plastic.

My question is, which side is in and which side is out on the replacement unit? Does it even make a difference? I would not think so, if it were not for the fact that the original does specify "in" and "out".