One Way Surveillance Mirror is a kind of mirror with high reflection ratio to visible light. When the product is used, the reflecting surface (mirror) must be the light facing surface or the side facing the outdoor. When the outdoor is brighter than the indoor, the unidirectional perspective glass is similar to the ordinary mirror. The indoor scenery can not be seen outside, but the outdoor scenery can be clearly seen indoors. When the outdoor is darker than the indoor, the indoor scenery can be seen outdoors, and the outdoor scenery can also be seen indoors. The clarity depends on the intensity of outdoor illumination.