The performer apparently shows two Cylinders, under one of which is a bottle, and under the other a glass. The magician makes a Magic pass, and the bottle and glass are found to have changed places, with the bottle now appearing under the Cylinder where the glass was, and vice versa. This is repeated a number of times and can be played for a lot of comedy.
For example an assistant can be chasing the bottle, and every time he selects a Cylinder, he finds the glass under it, while the bottle appears under the other Cylinder. After a few changes, as the magician is apparently talking to the audience, the assistant creeps up to both the cylinders and finds the bottle in one, which he steals away. He now smugly asks the magician to perform the trick again. The magician apparently unaware that the bottle has been stolen away, continues to perform the trick as before, leaving the assistant and the audience doubly amazed.
Powder Coated bottles and cylinders at a Bargain Price.