Mirrors in this category comprise of a clear float glass substrate, coated with a special thin layer of silver. One-way mirrors have an exceptionally high light reflection value (LR=50%) and an exceptionally low light transmission value (LT<2%).

This combination makes one-way mirror a very type of special glazing, its main application being covert observation between two spaces. In order to maintain privacy in the observing area, it is important to maintain a ratio of illumination level of at least 7:1 between the room that we want to observe and the room where the observer stands.