• Dexterous Brightstone Ring
• Item Level 245Disenchants into:
  [Abyss Crystal]: 1-2
• Binds when picked up
• Unique-Equipped
• Finger
• +76 Agility
  +76 Stamina
• Requires Level 80
• Equip: Improves haste rating by 50.
  Equip: Increases attack power by 101.
  Equip: Increases your armor penetration rating by 50.

Source

This item is sold by the following vendors for 35 :

•  Arcanist Asarina <Emblem of Triumph Quartermaster> in Icecrown
•  Arcanist Miluria <Emblem of Triumph Quartermaster> in Dalaran
•  Magistrix Iruvia <Emblem of Triumph Quartermaster> in Icecrown
•  Magistrix Vesara <Emblem of Triumph Quartermaster> in Dalaran

Patch changes

• Patch 3.2.0 (04-Aug-2009): Added. 
  

External links

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