Prestor's Talisman of Connivery

Prestor's Talisman of Connivery is neck armor that was highly sought after by hunters prior to the release of The Burning Crusade expansion due to it's high agility bonus. This item is also very valuable to meele dps classes rogue and fury warriors because of the + to hit chance. A hunter will reach max + hit effectiveness at + 6% from gear, while a rogue needs + 16%, and a fury warrior even more than that!

Source
This item drops from Nefarian, final boss of Blackwing Lair with an estimated droprate of 14%.