How did the magic of bottle caps changing into bottles change? Tell me what you know.

This bottle cap is prepared in advance and put in the bottle. Make a small hole in the trademark of the bottle, then put a bottle cap with the same iron plate in the bottle, then seal the trademark as it is, put on a magnetic ring, and adsorb the bottle cap inside to the trademark, so that the bottle cap can't be seen outside. When performing, take a normal bottle cap and pat it on the bottom of the bottle. At this time, loosen the hand with the ring, so that the bottle cap inside will fall off and the outside will be hidden by hand. It looks as if the bottle cap has gone through the bottle.