Created by Max Maven (aka Phil Goldstein), B'Wave is a classic among packet tricks.  If you look at lists of the all time most favourite and popular packet effects, you're almost certain to find B'Wave mentioned right near the top.   

The basic effect is that the spectator's selected queen is shown to be the only one face up.  Then as a kicker the remaining three cards are shown to be blank. The routine is somewhat similar to The Parade of the Kings, which is an obvious influence, but the final reveal makes it an even stronger effect.

B'Wave involves just four cards, has minimal set-up and handling, and is very easy to learn and perform, and is largely all about the presentation.  With the right patter, it can generate a very strong reaction.
 It can be performed either as a magical effect or as a feat of mentalism, the latter being the recommended and most common way to do it.

This is an excellent packet trick that is ideal for strolling magic, or for keeping in your pocket or wallet whenever you are called upon at short notice to do a card trick. Highly recommended!