The 3M Notebook Privacy Computer Filter uses patented 3M microlouver technology to make on-screen data visible only to persons directly in front of the monitor. Passersby can only see a dark, blank screen. Your screen view remains sharp and clear with improved contrast and privacy without blurring. The filter is easily attached and removed, and it stays in place even when the notebook is closed. The filter is compatible with 17.0" widescreen laptops and LCD screens.