Online: Robes of Destruction Mastery
2 items: Adds 25-1096 Maximum Magicka
3 items: Adds 19-833 Spell Critical
4 items: Adds 3-129 Spell Damage
5 items: While you have a Destruction Staff equipped, your Max Magicka is increased by 66-2840.
The set consists of light armor and jewelry in all slots, as well as weapons and shields of all types.