We can hang a convex lens, eight diagrams mirror or five emperors' money at the door. The convex lens itself is like a turtle shell, which has the function of reflection. Of course, when something evil enters, the convex lens can also help us to resolve it.
There must be eight normal phenomena corresponding to the Eight Diagrams Mirror, including the cosmic balance information condensed by Taiji diagram, which may play a role in dissolving evil spirits or transforming the gas field, and may also help us get rid of some adverse effects on the terrain and ourselves.
The efficacy of the five emperors' money itself can be improved by the efficacy of the convex lens, but it should be noted that the real five emperors' money is effective, and some imitations of the five emperors' money are actually ineffective.