Stormrage Cover (tier 2)

The Stormrage Cover is part of Stormrage Raiment, the raid Tier 2 armor set for Druids.

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.