Double Mental (Blue) or (Red) by Dominique Duvivier (GV$5)

Comes with a $5 gift voucher on your next purchase :)
Does not apply to MAP (minimum advertised pricing) products. 
 
The spectator and the magician each THINK of a card.

The deck is taken out of its case and, unbelievably, BOTH CARDS ARE FOUND NEXT TO EACH OTHER!

So what's most weird: that the magician's card is next to the spectators, or the other way round?

In fact, the weirdest thing is that when the spectator's thought card is turned over, it's the only card in the deck with a different-colored back!

A disturbing and magnificent effect!

Strong points
An absolutely killer effect
Extremely easy to make.
Very quick to reset.
Guaranteed success!
Provided:
The special deck in Bicycle quality.
Online video instructions.