• Pendulum of Infinity
• Item Level 239Disenchants into:
  [Abyss Crystal]: 1-2
• Binds when picked up
• Neck
• +64 Agility
  +70 Stamina
• Blue Socket
• Socket Bonus: +4 Agility
• Requires Level 80
• Equip: Improves critical strike rating by 48.
  Equip: Improves haste rating by 41.
  Equip: Increases your attack power by 86.
• Sell Price: 7 56 23

Source

This item drops from General Vezax on hard mode in the 25-man version of Ulduar.

Patch changes

• Patch 3.1.0 (14-Apr-2009): Added. 
  

External links

• Battle.net (EU)
• Wowhead
• Thottbot
• WoWDB