A fun “mental” gag from Bob Solari.
Display six colour-coded keys. Invite five audience members to each select a key.
Leaving one key for you, explain that only one key opens the lock.
During the routine, the spectators can exchange keys including the one reserved for the magician.
In the end, only the magician's key opens the lock.
You can perform many different presentations!
Well made and works every time!