This is a two-way mirror (also called a 'magic' mirror), originally from a London nightclub. The side that gets the light is mirrored, and the darker side can see through. Of course you could use as a usual mirror against a wall but if you put between an internal wall as a 'window' set within a frame, you could get both effects.
Slightly weird idea but apparently used for theatrical or privacy purposes, or for artistic composition.
Height: 136.5cm
Width: 80cm
Depth: 6cm
Collection only from near Redhill, RH1.