kun tu bzang po klong drug pa'i rgyud
One of the 18 Dzogchen Tantras.
Note: The names, numbers and the tantras themselves in these lists may vary from teacher-to-teacher, tradition-to-tradition. Some call for 17, some call for 18, and some add still an additional tantra making the total 19. See also Seventeen Tantras of the Great Perfection and Eighteen Dzogchen Tantras for further reference.