Privacy filter is designed to protect delicate, 18-1/2" wide-screen LCD monitors from damage & to secure confidential information. Microlouver technology creates a restricted viewing angle. Image is only visible to those directly in front of the screen. Side view is black. Privacy filter eliminates glare & increases contrast. Protective, overlay LCD surface is designed for a built-in look. Filter stays in place when your notebook is closed. Aspect ratio is 16:9.