The magician picks up a card box as if to demonstrate a card trick and discovers that it rattles. Opening it, he tips from within four 3-volt circular batteries. Taking one of the batteries into his fist, he squeezes it and on opening the hand it is seen to have changed to a more powerful AAA battery. Holding this battery at the fingertips, the performer passes his other hand across it and causes it to visibly change to a larger AA battery.
Finally, he clasps his two empty hands together and on parting them reveals that now a square 9-volt battery has magically appeared!
No gimmicks are required, just a card box and a few batteries plus some low-level sleight of hand.
video 7:59.
