This very deceptive trick has always been one of my favourites. It has been around for many years. It has been used as a stage version by for example Dutch magician Fred Kaps as you can see in the video bellow (in Dutch).
Recently (well, more or less, both are out of production and have become very collectible), versions have been made by Magic Wagon and Limited Editions Magic.
Left: Magic Wagon - right: Limited Editions Magic
The front and back panels in the Magic Wagon version are held together with a piece of wood on top. There is a recess on the bottom where the panels are placed into. This makes it very stable.
Lt. Editions Magic version uses magnets.
As you can see the MW version is taller. Both are exactly the same width however.
The mechanism is exactly the same. Both work very fluently. However,
- the 'middle' position on the MW version is indicated with a mark,
- the 'middle' position on the Lt. EM has a small recess which you can 'feel' and which therefore makes it possible (or at least, easier) to place the necessary thing in the middle position without looking.
Luckily both come with a glass panel, not a plexiglass one. I refuse to buy magic tricks that use plexi; it is almost impossible to remove markings/scratches which are almost always present after many uses.
The glass panel of the Lt. EM version (right on the photo) is about 1 mm wider. The panel of the MW version (left on the photo) is taller.
Both glass panels are perfectly clear of course - I used a red pillow with some motifs beneath them to make a picture to compare them which wasn't the best idea it seems ... .
The MW version is made intirely of wood. The Lt. ED version uses wood and brass which also makes it quite a bit heavier.
Both versions have the same build quality: excellent.
Both versions are very deceptive, however the Lt. EM version looks a bit more 'impossible' because of its smaller size and more importantly the two brass 'pilars' on the left and right side.