Plagueheart Shoulderpads

Plagueheart Shoulderpads are shoulder armor for warlocks. They are part of the Plagueheart Raiment armor set.

Source
The shoulderpads are a quest reward from Plagueheart Shoulderpads (quest), crafted by a vendor from the Desecrated Shoulderpads, an item which drops from Patchwerk, Grobbulus and Gluth who currently reside in Naxxramas.