Brainwave Deck

The Brainwave Deck is similar to the Invisible Deck and performed in the same way; however, to locate the selected card the deck is spread face-down and the named card is the only one that's face-up. As a second climax to the trick, this card is turned face-down and shown that its back color is different from that of the rest of the deck, thus proving that that the magician really did know what the spectator would say in advance and didn't just secretly turn the card over.

First description in The Jinx N° 49, oct. 1938, page 341. Brain Wave Deck by Dai Vernon. Marketed in november 1938 as The Brain Wave Deck.