You remove a flat, invitation-size envelope from your pocket and dump out an "invisible deck". You direct a spectator to freely "destroy" these imaginary cards until only a single card remains. Let's say the Queen of Diamonds.
The spectator tosses the invisible Queen of Diamonds toward the envelope. You. then slowly and cleanly remove the "one & only " card in the envelope. It's the spectator's "one &only" Queen of Diamonds.
The Envelope is clearly seen to contain no other cards after the "one &only" card is removed.
The card in the envelope is always the exact card named by the spectator.
Uses just one envelope.
No palming, switching, or loading of the envelope.
Resets in seconds.
Perform sitting, standing or while aimlessly wandering around.