Does the Purest Sleep Diffuser have timers? January 23, 2019 19:36 Yes, the unit has three timer options: 1-hour, 2-hour, and continuous use. Related articles What is the difference between the Rohm and Hushh? How long does the Purest light stay on? Will the Purest Sleep Diffuser work with any essential oil? What is a “sound machine”? Which sound machine is best for me?