Crown of the Lost Protector

Crown of the Lost Protector is a tier 7 armor token. It can be exchanged in Dalaran for the following items:
 * Valorous Dreadnaught Greathelm
 * Valorous Dreadnaught Helmet
 * Valorous Cryptstalker Headpiece
 * Valorous Earthshatter Faceguard
 * Valorous Earthshatter Headpiece
 * Valorous Earthshatter Helm

Source
This item drops from Kel'Thuzad in the 25-man version of Naxxramas.