There is no mark, no devices attached to cups or nails, no magnet, no thread etc.
Even everything can be checked from start to finish and you will make your spectators hysterical with this dangerous trick.
You can also play other tricks with ordinary objects you meet around you, with this method you can guess the object chosen by the audience or the body part of the audience that has been touched without looking at all.
Because you really do this trick yourself. So what do you wait? Get to learn now!