Blackout Privacy Filter is designed to prevent unauthorized viewing and help ensure the privacy of on-screen data on your 21.5" LCD wide-screen monitor. Microlouver technology creates a narrow viewing angle so the image is only visible to those directly in front of the screen. Side view is black. Frameless filter overlays LCD surface for a built-in look. Filter also eliminates glare, increases contrast and protects LCD surface from damage. Aspect ratio is 16:9. Filter includes a microfiber cleaning cloth.