Vestments of the Warlock is a light armor set. When you fall below 25% Magicka, restore 11350 Magicka. This effect can occur once every 45 seconds.
A Stamina version of this set (Trappings of Invigoration) drops in Fang Lair.
The Vestments of the Warlock set is part of the base game. It drops in Selene's Web in Reaper's March. Each set item is bound on pickup. You can acquire light armor, weapons and jewelry of this set in the Breton motif style.