Dragonstalker's Helm (tier 2)

The Dragonstalker's Helm is part of the Dragonstalker Armor set, the Tier 2 armor set for Hunters.

Source
Prior to the release of patch 3.2.2, this item dropped from the level 60 version of Onyxia. It has since been moved to Nefarian in Blackwing Lair, along with the rest of the tier 2 helms.