The window/film assembly must have a regular light transmission factor or transparency index, meaning the light transmission level, expressed as a percentage (ratio between the transmitted luminous flux and the incident luminous flux, multiplied by 100), as indicated in the following table, depending on the type of vehicle and window in question. This value must be marked on the film through the incorporation of an embossed and indelible stamp, which will also indicate the name and unique tax number (RUT) of the installer, so that this information can be read from outside the vehicle.