Color: Black Privacy Filters keep confidential information private. Only persons directly in front of the monitor can see the image on screen; others on either side of them see a darkened screen. From the Manufacturer Privacy Filters allow you to work privately in public places. privacy technology darkens on-screen data when viewed from the side, and provide higher clarity than competitive filters. This Privacy Filter is custom-cut for the Apple 21.5 -inch iMac. The filter application system features an optically clear adhesive designed specifically for display screens. Testing proves that, when the adhesive is kept clean, filter can be repositioned hundreds of times.