This is a remarkable trick. But although it's almost self working it does require a little bit of practice to make the trick work. The biggest problem I found was if you put too many cards back into the box then the trick wont work, too little and it will work but not smoothly, so getting the judgement right is a little tricky at first (but not critical).

The other down side is although it's very true that it's examinable it's not quick(instant) to reset so it's not very practical for table hopping!
A beautifully made item, reasonably priced and one hell of a trick.
Definitely worth getting!