Privacy filter in portrait orientation works in your 21.5" wide-screen monitor to help protect your screen from everyday scratches and dust, and help keep the information displayed on them private. Advanced Microlouver technology delivers effective "black out" privacy from side views outside the 60-degree viewing angle. You get crisp image clarity on your display while visual hackers with side views are kept in the dark. Wide-screen filter reduces 35 percent of blue light transmission from the display and helps reduce reflections so you see your screen clearly with pristine image clarity. Reversible design includes a glossy side and a glare-reducing matte side that helps hide fingerprints. Scratch-resistant privacy filter with 16:9 aspect ratio attaches in two ways: attachment strips and slide-mount tabs. Viewing dimensions are 18-3/4" x 10-9/16" (477mm x 268mm).