The value of pipe #690 is n/a points.
This is the third of these that have turned up in as many months. The two previous examples were black; now we have a green one. We still don't know who or why over-stamped these the pipes with this Venturi in an oval, but we have found out how. We can't be sure of when either, although my theories are expounded in the notes about the black billiard. I have not assigned a point value to these pipes until we have more information.