
I forgot I owned this lol - I just read your description and thought, "Hmm .... hang on a minute - that sounds familiar". I then proceeded to rummage through my "magic drawer" and I found it heh heh
I'm trying to steer away from gimmicks so I haven't used this in a while but from what I remember there are pluses and minuses with this trick
For starters I had the same problem as Cardza - my gaff started falling apart and coming unstuck.
When it comes to the reveal of the card in the envelope - the envelope cannot be handed out, although you can cleanly show that there is only 1 card and this matches their selection. There is no switching of envelopes - it stays in full view the whole time
I've gotta admit that this is not for everyone. It is, however, quite an ingenious lil' trick and if presented correctly will be very powerful.
Any questions - feel free to PM me
