This is a very nice trick wich I have used a lot in close up situtations. No electronics involved. Practice in front of a mirror and see to it that you are not surrounded. The fact that it is the spectator who puts the first box into the second box makes him feel the boxes cannot be gimmicked. You will need good eyes in low lighting though. There is one little detail where the prop could be improved. I would prefer red and white or black and white used instead of bare metal and red. Bare polished metal takes on the colour it reflects and is thus sometimes difficult to distiguish. If it were not for these small points of criticism I would give the trick 5 stars. Recommended.
Kaarlo von Freymann, Helsinki, Finland