Miraak's Robes

Acquisition
Miraak's Robes can be acquired from the remains of Miraak at the conclusion of the quest "At the Summit of Apocrypha", along with his boots, gloves, sword, and staff.

Enchantment
Wearing this piece of armor grants the following bonuses:
 * Spell Absorption: 15%
 * Chance on hit to spawn a tentacle explosion.

The spell absorption can be further increased by wearing Miraak's Gloves and Miraak's Boots, which each add another 5% to the total, granting a maximum of 25%.

In addition, the robes cannot be disenchanted to learn its effects.

Usefulness
Miraak's gloves, boots and robes potentially grant a total of 25% Spell Absorption, however they can be used to help achieve a figure of over 100% if used alongside the The Atronach Stone (50%) and the Atronach Alteration perk (30%).

This means a 100% Spell Absorption, if triggered, will negate all damage from any incoming spells and will also restore the Magicka equal to the base cost of casting a spell.