It is a 2 way NANOBLIND privacy filter for 21 inch monitors. The viewable screen size is W 16 3/16 inch, 411mm x H 12 3/8 inch, 314mm. NANOBLIND privacy filter shields or blacks out your screen for your privacy with confidential information against shoulder surfers, visual hackers, wandering eyes and prying eyes beside you. Nobody can see the contents when viewed from both left and right sides at 30 or higher degree viewing angle while you see crystal clear images on the screen. It has UV 3H hard coated surface to be protected from scratches, scuffs and fingerprints. It has anti-glare coated surface for comfort eyes. It is easy to attach on the monitor screen and removable & reusable multiple times. It is suitable for use on computer screens in corporations handling confidential information.