Power valve identification

There was a bunch of those that came through without numbers on them. The only way to know what it is in that case is to pull a vacuum on it and see where it opens. You should do that anyway because the numbers are very accurate.

And as above, a picture will help. Also look on the hex side of the valve. It could be stamped there.
I'll try to get a clear pic up. There are no numbers stamped on the side.