Magicka Furnace is a light armor set. When you take damage from a melee attack while you are under 80% Magicka, restore 8000 Magicka. This effect can occur once every 30 seconds.
The Magicka Furnace set is part of the base game. It drops in Direfrost Keep in Eastmarch. Each set item is bound on pickup. You can acquire light armor, weapons and jewelry of this set in the Wood Elf motif style.