Non-dual Tantras
Non-dual Tantras (Skt. advaya tantra; Tib. གཉིས་མེད་ཀྱི་རྒྱུད་, Wyl. gnyis med kyi rgyud) - one of the three classes of Highest Yoga Tantra according to the Sarma tradition. It includes tantras such as the Kalachakra Tantra. The Sakya tradition considers Hevajra Tantra to be a non-dual tantra.