How do I turn the pen on/off?

Disclaimer: Please use responsibly. Electronic vaporizer products are intended for use by persons of legal smoking age. The Rokin vaporizer products are not intended for use by non-smokers or by children, women who are pregnant or breastfeeding, or persons with or at risk of heart disease, high blood pressure, hypertension, diabetes, or taking medicine for depression or asthma. Discontinue use and consult a physician if you experience misuses symptoms such as nausea, vomiting, dizziness, diarrhea, weakness and rapid heart-beat or hypertension. Not for use with tobacco or nicotine. If used with Nicotine: Nicotine is addictive. For use by existing smokers aged 21 years or over, as an alternative to tobacco cigarettes. Not to be used by children, pregnant or breastfeeding women or persons in ill health. If unsure of use please consult your doctor. Using tobacco or nicotine products in Rokin products may be harmful to the devices.