The Targus 18.5" LCD Monitor Privacy Filter is designed to fit 18.5" widescreen LCD monitors with 16:9 ratio screens. To protect your information, tiny vertical blinds on the surface of the privacy screen narrow the viewing angle so data is only visible directly in front of the monitor up to 45 degrees away from the center of the screen. Onlookers will only see a dark unclear screen when attempting to view the information from a side angle. In addition to providing security, the screen also blocks the glare to help reduce eye strain.