First page of MMO champion:
http://db.mmo-champion.com/i/78479/souldrinker/
Very interesting proc, and note how it isn't unqiue and can be used in either hand.
For you SMF warriors, Frost DKs, and Combat Rogues out there...would a pair of these make you absolutely rediculous in PvP given a relatively high proc rate and low cooldown?
I know I'll be tempted to give it a whirl when my guild downs heroic Deathwing within 2-3 weeks of the top 20 world guilds.