Trappings of Invigoration is a medium armor set. When you cast an ability while under 33% Stamina, you restore 9000 Stamina. This effect can occur once every 1 minute.
A Magicka version of this set (Vestments of the Warlock) drops in Selene's Web.
The Trappings of Invigoration set is part of the Dragon Bones DLC. It drops in Fang Lair in Bangkorai. Each set item is bound on pickup. You can acquire medium armor, weapons and jewelry of this set in the Fang Lair (unique) motif style.