Niffen Tube 3 (unknown manufacturer) 8" high and 2" diameter

NOTE: This is used.  In good condition. 
It came from a magician's estate. 

A Niffen Tube is a clever switching device.
Made with caps on both ends, the tube secretly slides even with one end or the other.
Of course, the spectator sees a tube that has only one cap end.
By placing an item (say a red silk) into the tube, and closing the cap, the performer can secretly push the tube so that when he opens the cap, he is opening the other side.
And this other side holds a different item, say a blue silk.
So the effect is that the spectator sees a red silk go into the tube, and a blue silk come out!

About 8" high and 2" diameter.