The yoga scholars James Mallinson and Mark Singleton write that "pure breath-retention" (without inhalation or exhalation) is the ultimate pranayama practice in later hatha yoga texts. They give as an example the account in the c. 13th century "Dattātreyayogaśāstra" of "kevala kumbhaka" (breath retention unaccompanied by breathing). They note that this is "the only advanced technique" of breath-control in that text, stating that in it the breath can be held "for as long as one wishes". The "Dattātreyayogaśāstra" states that "kevala kumbhaka" gives magical powers, allowing the practitioner to do anything: