Purifier

 set was the first set available in Tabula Rasa. More items of the same set you are using at once more bonuses you get.

 set is connected to the Velon Hollow operation. 3 armor parts are rewards from the missions Mountain Spring Toxins (Vest), The Better Half (Helmet) and Holy Vengeance (Legs). You can choose between Bio, Mech, Stealth and Graviton versions. Weapons are a random drop from enemies in the instance.