Allows an imac post 2012 to be mounted on a mount with vesa hole patterns from 75x75 to 100x100mm further explanation about vesa in product description you would use this vesa conversion plate when you want to alter the vesa compatability of a screen to suit a mount with a differing vesa pattern the adapter is compatible with 21 5 to 27 screens 5 year warranty newstar have over 20 years experience of providing high specification mounts you get what you pay for