Originally Posted by nasty_rabbit
Is it smaller diameter or smaller thickness? If it is smaller thickness and possibly green or red it may be for the ball lock connection on the top of the keg where your liquid line connects to.
It fits right around the dip tube but it's a lot thinner and less bulky. It's black and not the o rings for the posts. I put those on as well recently so I know what those are like. It doesn't seem tight at all like it would create a seal. When you screw on the post is it supposed to push down on the dip tube to put pressure against it?