"Kevala Kumbhaka", when inhalation and exhalation can be suspended at will, is the extreme stage of "Kumbhaka" "parallel with the state of Samadhi", or union with the divine, the last of the eight limbs of yoga, attained only by continuous long term pranayama and kumbhaka exercises. The 18th century "Joga Pradipika" states that the highest breath control, which it defines as inhaling to a count ("mātrā") of 8, holding to a count of 19, and exhaling to a count of 9, confers liberation and Samadhi.