Robes of Destruction Mastery is a magicka-based light armor set. While you have a Destruction Staff equipped, your Max Magicka is increased by 2400.
The Robes of Destruction Mastery set is part of the base game and can be found in the Dragonstar Arena in Upper Craglorn. Each set item is bound on equip. You can acquire light armor, weapons and jewelry of this set in the High Elf motif style.