Item:Stone of Experience

The Stone of Experience is a special item that gives a character enough experience to instantly reach level 16, then grants a set of level-appropriate bound gear for that level.
 * Official news page
 * Announcement/discussion thread

Players who have purchased Menace of the Underdark AND are level 16 or higher, are eligible to receive the Stones of Experience from a special NPC, Braddack Bouldershoulder in the Harbor, near the Marketplace entrance. Players who have used the Stone receive an exclusive Snow Panther Cub Creature Companion. This promotion ends August 20th.

XP math
You can use a Stone on any character that is between level 8 and level 15.