Great children's routine.
Show a tube of Menthos. Put it into the black tube.
Do whatever routine you like and at the end the Menthos have disappeared and appear somewhere else!
I tend to put a red silk into the fake tube, make a red silk disappear via a thumb tip, and then the red silk appears in the black tube and the real Methos...well, wherever you hid them before the gag. I am even including 4 real packs of Menthos to get you started immediately!
There are instructions included which advises use of a change bag etc and is very good but there are plenty of different ways to do it.
I have used this a few times. New it costs £40.
This is the only one I have. That's it, once it's sold, it's sold.