Rattlecage is a heavy armor set. Gain Major Sorcery at all times, increasing your Spell Damage by 20%. The 5-piece set bonus also adds 100 Spell Damage.
The Rattlecage set is part of the base game. It drops in Vaults of Madness in Coldharbour. Each set item is bound on pickup. You can acquire heavy armor, weapons and jewelry of this set in the Daedric motif style.