Chromatic Mantle of the Dawn

Chromatic Mantle of the Dawn is a special enchantment for shoulder armor that adds resistances to all schools of magic.

Source
This item is sold by the following vendors for : Note that you need to have completed the quest Quest:Chromatic Mantle of the Dawn to be able to buy it, which is unavailable since patch 4.0.3a.
 * in Tirisfal Glades
 * in Western Plaguelands
 * in Eastern Plaguelands