Bill Tube with Lock

The performer borrows a dollar bill which is initialed by a spectator. The bill is now folded, secured with a rubber band and placed within the folds of a hank, held by a spectator. The performer now displays a small brass tube with threaded lid and a brass bar running through it. This is given to the spectator to hold in their free hand. The performer now snatches the hank from the spectator's hand and the hank proves to be empty! The dollar bill has vanished. Unscrewing the brass tube, the spectator finds the missing bill inside!