Dhu Bleidd (Elder Speech: Black Wolf) is an armor enhancement in The Witcher 2: Assassins of Kings.
It is found in a chest in Vergen outside Saskia's quarters. The house can be identified as two Scoia'tael stand guard outside. Geralt immediately appears outside here after The War Council, so this would be a good time to get it. It can also appear as loot randomly on dead Scoia'tael in Chapter I.