Ergotech Grommet Mount Accessory for Freedom Arm (FDM-GROM-G) Compatible with 24-inch iMac (aluminium and glass) 27-inch iMac (late 2009, mid2010, and 2012) 24-inch LED Cinema Display, 27-inch LED Cinema Display 27-inch Apple Thunderbolt Display Offers 14" of dynamic one-touch height adjustment iMac adapter plate included Capacity: 20-30.8lbs Tilt: UP 90Degree, Down 45Degree