The Mentalist borrows a wedding ring from a person out of the audience, then he hangs the ring in the bow of the combination lock.
After that, the combination lock is closed.
The mentalist admits, that he unfortunately forgot the combination! Some spectators may check the lock, but even they can not open it.
Now the mentalist tries to open the lock with the power of his mind. To do so, the performer asks the owner of the wedding ring in which year he got married. Would´t it be amazing, if the lock opens with this date combination?
And it does! This mental lock can also be used in conjunction with the PERFECT PREDICTION.