The AC-GC grommet accessory allows attachment of monitor mounts via desk grommet holes. It is compatible with grommet holes from 60mm to 80mm in diameter and supports desk surfaces from 18mm-36mm in thickness. It also allows cables up to the size power and VGA plugs to pass freely through the discrete opening. Diameter of top plate is 112mm Compatible with Atdec VF-, AF-, and AWM- posts Available in black and silver All mounting hardware included