3m Vision Filter LCD/Laptop 21.3" Decreases Viewing Angle Clipmount PF21.3 PF 21.3 fits standard desktop LCD monitors with a diagonally measured 21.3" viewable screen. Actual filter dimensions are12.776" high x 17.028" wide. This filter is designed for standard desktop LCD monitors with screens that appear more square than rectangular. Great for high traffic areas or open cubicle offices. Privacy filters keep confidential and private information secure. Utilizes 3M's microlouver privacy technology so only persons directly in front of the monitor can see the data on screen. Passersby see only a dark, blank screen. Never blurs or distorts on screen data. Reversible for either glossy or matte screen finish. Reduces reflections when used with the matte side facing you. Helps protect fragile LCD screens from scratches and fingerprints. New easy on easy off attachment system. Easy to attach and remove.