RETROFlex-louvers are assembled like venetian blinds. They are installed either on the interior or within a closed double-layered facade.

The aluminium louvers act as efficient retro-reflectors by theirprismatically micro-structured surface. The microstructure is embossed into the aluminium utilizing the mathematics of a Fresnel mirror.  The smooth surface of the lower side is either white or alu-reflective. In the upper area of a window, the blinds can be installed inversley to improve the natural daylighting of the interior.