The magician borrows a bill from a spectator and has it marked. The bill is then rolled into a tube and a rubberband is placed around it. It is then inside a hanky given to a spectator to hold. Next, the bill tube is introduced and shown to be locked and secure. There is no apparent way to get into the tube without unlocking it. The tube is given to another spectator to hold. On the count of three, the hanky is shaken and shown to be empty. The magician then introduces a pair of keys. They are given to the spectators, who unlock the tube revealing the signed bill inside! Precision made brass.